Keywords: Pest management
Feral rabbit numbers are booming, so do myxomatosis and calicivirus still work, and what’s next for biocontrol?
35522Belinda Smith, ABC News, 2026-03-12 09:20:38.
If you've noticed more feral rabbits around than usual, you're right. Much of Australia is experiencing a bunny boom, driven by consecutive years of good breeding conditions. But with an estimated 200 million feral European rabbits (Oryctolagus cuniculus) currently hopping around the continent, you might also have wondered if the viruses that kept their numbers down in the past — myxoma virus and a calicivirus that causes rabbit haemorrhagic disease — still work. Heidi Kleinert, national feral rabbit management coordinator at the Centre for Invasive Species Solutions, says ideally Australia needs to develop and release a new biocontrol every 10 to 15 years to keep rabbit numbers as low as possible. "It takes time to find another effective virus that we know is targeted specifically to rabbits, and we know is proven and tested and has approval from government organisations," Ms Kleinert says. "Across Australia, we're seeing more rabbits in peri-urban and urban areas. That's why we need that continuous pipeline of biological control, because in these areas we can't use bait and toxins close to domestic housing and domestic pets." So how do myxoma and rabbit haemorrhagic disease viruses work, and what goes into finding the next bunny biocontrol weapon?
The evolution of the sterile insect technique from concept to global application
35432Kostas Bourtzis, Marc F. Schetelig, Walther Enkerlin, Rui Pereira, Comprehensive Molecular Insect Science, 5:180-211. 2026-02-10 12:07:51.
The sterile insect technique (SIT) is a species-specific, environment-friendly and cost-effective method for controlling insect pests and disease vectors. It involves colonization and mass-rearing of the target species, sterilization, typically by ionizing radiation, and systematic release of sterile insects, preferably males, into the target area. Released sterile males induce reproductive failure in wild populations, leading to suppression, containment, prevention of establishment, or local eradication of a target insect pest population. First demonstrated over a century ago, SIT has evolved into a robust and widely adopted tool within area-wide integrated pest management (AW-IPM) programs. It has been successfully applied against several major agricultural and veterinary pests, often achieving high returns on investment. In the context of accelerating climate change and global species invasions, further development and deployment of SIT are essential. Future efforts should focus on enhancing cost-effectiveness, operational scalability, and integration with complementary technologies for sustainable pest and vector management.
Generating cisgenic sexing strains in insect pests
35435Davydova, S., Liu, J., Kandul, N.P. et al., Communications Biology, 2026-02-05 18:20:56.
Insect pest population control via sterile insect technique markedly benefits from separation by sex prior to release. To simplify this process, traditional genetics has been deployed to develop genetic sexing strains (GSSs) for several disease vectors and agricultural pests of vast economic significance, although very few are applied in the field due to associated fitness costs and instability. In this study, we generated a method to engineer cisgenic GSS (CGSS) in insects. We use CRISPR/Cas9-mediated homology-directed repair to seamlessly translocate a sex-specific alternatively spliced intron into a dominant phenotypic gene generating a genetically stable strain that enables sex-sorting by eye. To achieve this feat, we use Ceratitis capitata as our model and relied on the sex-specifically spliced intron of its endogenous transformer gene, which we seamlessly inserted a copy into the pupal colouration white pupae gene. This minimal modification resulted in the generation of a homozygous strain we term IMPERIAL that was genetically and phenotypically stable where all female pupae are brown while male pupae are white with overall good fitness. By minimally editing the genome, our novel CGSS approach can be applied to other pests that may aid more efficient and economically suitable pest control.
Precision pest management: Genome editing tools, specifically CRISPR/Cas9 and future prospects
35424Ankush Saini, Neha Sharma, Nidhi Sharma, et al., Pesticide Biochemistry and Physiology, 218. 2026-02-03 15:42:17.
The growing resistance to synthetic insecticides and Bt toxins, alongside persistent crop losses despite heavy pesticide application, highlights the urgent need for safer, sustainable and efficient pest management strategies. This review presents genome editing as a precise and versatile approach to reduce pest impact by altering fertility, feeding patterns or vulnerability, while protecting beneficial organisms. Among the genome editing tools, CRISPR/Cas9 (Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated protein 9) is one of the most promising genome editing techniques in insects. It facilitates targeted functional studies, integration with RNAi and dual-expression systems and gene drive applications. Deployment is envisioned in two phases, initial laboratory modification followed by regulated field release, with a strong emphasis on biosafety through terminator genes, marked individuals for gene flow monitoring, optimized dosages, stringent screening and long-term ecological surveillance, along with transparency and adherence to international safety protocols. Significant challenges encompass delivery efficiency, identification of edits, off-target mutations, dose-related efficacy and sterility, unstable transmission and resistance development. Innovations such as base and prime editing minimize unintended mutations by circumventing double-stranded breaks (DSBs), while paratransgenic strategies targeting gut symbionts offer supplementary avenues; plant-mediated insect gene editing emerges as a promising frontier. Overall, carefully regulated trials aligned with policy frameworks and stakeholder involvement are vital to assess effectiveness in natural environments and achieve targeted, dependable and ecologically responsible pest control.
Scientists in Australia have created a genetically edited cane toad that gets stuck in the tadpole stage and attacks the plague before it spreads.
35365Noel Budeguer, Click Petróleo e Gás, 2026-01-16 10:59:37.
Australia has begun testing an unusual idea to combat one of the country's most persistent biological invasions: creating tadpoles of the cane toad who have never seen adults. The goal is to cut the problem off at the source, before the animals grow, leave the water, and move into new areas, increasing the impact on native wildlife. The proposal is noteworthy because it shifts the focus of control. Instead of targeting adults who have already spread out, the action targets the point where the population begins, the spawning grounds. The cane toad, a species Rhinella marina, it was introduced in Australia in 1935 and spread rapidly through northern regions. The species adapted quickly, encountered few natural barriers, and came to dominate environments where native animals cannot compete on an equal footing. Over time, the problem ceased to be isolated and became a constant threat to entire ecosystems. The adult stage is what allows the cane toad to move long distances and occupy new territories. The idea behind the project is to prevent this transition, keeping the animal confined to the aquatic environment and reducing the arrival of adults in the natural habitat. In practice, the plan attempts to halt the spread of the pest before it "jumps" out of the water. The technique uses CRISPR Cas9 to alter a point related to the hormonal control of metamorphosis. The target is the production of thyroxine, a hormone that triggers the transformation of the tadpole into an adult frog. Without this signaling, the animal remains in the aquatic phase and does not complete the cycle that would make it an even more aggressive terrestrial invader.
Identification and evaluation of two testis-specific serine/threonine kinase genes from multi-tissue transcriptomes as potential genetic targets of sterile insect technique in Zeugodacus tau
35439Weijun Li, Cuikang Xu, Hongshi Chen, et al., Pest Management Science, 2026-01-15 18:32:40.
Zeugodacus tau (Walker) is a notorious agricultural pest causing significant economic losses in vegetable production for many years. Sterile insect technique (SIT) has emerged as an environmentally sustainable pest management strategy. However, discovery of molecular targets applicable for SIT implementation in Z. tau still constitutes a significant research gap. We conducted comparative transcriptome analysis of four male tissues (midgut, Malpighian tubules, fat body, and testis), identifying 9653 differentially expressed genes (DEGs) with predominant testis enrichment. Bioinformatics screening revealed 3020 testis-specific highly expressed genes showing significant functional enrichment in cytoplasmic translation, cytosolic ribosome assembly, and oxidoreductase activity. Quantitative real-time PCR (qRT-PCR) assay was utilized to confirm 10 testis-specific genes, including two serine/threonine kinases (ZtTSSK1 and ZtTSSK3) which were significantly enriched in spermatid development. Fluorescence in situ hybridization (FISH) localized the two genes specifically to the transformation zone of Z. tau testis. Functional characterization via RNAi bioassay demonstrated that suppression of ZtTSSKs expression levels reduced spermatozoa number and impaired male fertility. These results establish ZtTSSKs as crucial regulators of male fertility in Z. tau and identify them as potential molecular targets for developing SIT-based interventions against this economically significant pest.
Sterile insect technique reduces cabbage maggot (Diptera: Anthomyiidae) infestation in root crucifers in Canada
35337Anne-Marie Fortier, Allen Bush-Beaupré, Jade Savage, et al., Journal of Economic Entomology, 118:2710–2717. 2026-01-07 11:20:58.
The cabbage maggot (Delia radicum (L.)) is a major pest of brassica vegetables in Canada that has traditionally been managed with soil-applied insecticides. However, recent regulatory restrictions on key products such as chlorpyrifos have created a pressing need for alternative solutions. This study evaluates the sterile insect technique (SIT) as a control method for the cabbage maggot in root crucifers. Large-scale field trials conducted from 2019 to 2022 in Quebec (Canada) demonstrated significant reductions in D. radicum infestations in radish and daikon crops. Quality control measures confirmed the effectiveness of sterilization on cabbage maggot, with minimal impact on male performance. The results suggest that the SIT is a promising, environmentally friendly alternative to chemical control for cabbage maggot management. The study further highlights the importance of optimizing release strategies and improving predictive models to guide deployment. Overall, the SIT offers growers a viable option to reduce reliance on insecticides while maintaining crop health and yield.
Behavior modification in fruit flies through male annihilation technique: field applications, olfactory mechanisms, and future directions
35329Liu, Wei; Zhang, Sijia; Wang, Guirong, Entomologia Generalis, 45:1565 - 1576. 2026-01-06 14:51:47.
The male annihilation technique (MAT), as a method of insect behavior manipulation, is an environmentally friendly approach that has been successfully applied in over 150 fruit fly eradication programs worldwide. Despite their effectiveness in integrated pest management programs, concerns have long persisted about the safety of the primarily used male lures – particularly regarding the potential toxicity of methyl eugenol (ME). In this review, we propose a novel attractant screening and validation system for the future improvement of male lures, based on recent advancements in functional genomics and genetic manipulation technologies achieved in tephritid fruit flies. This system is built upon our knowledge of tephritid fruit flies’ core olfactory signal transduction pathway (“Male lures → Odorant receptors → Odorant receptor neurons → Glomerulus”). The working pipeline is centered around a transgenic Bactrocera strain with labeled male lure-responsive olfactory receptor neurons (ORNs) as the key targets. Electrophysiological responses and calcium activity serve as the readouts, while the decision criteria focus on increased intensity, stability, and specificity of neural activation induced by candidate compounds. This pipeline, compared to traditional behavior-first methods, enables the efficient screening of computationally identified candidate compounds and provides a foundation for evaluating their field stability and safety. More importantly, it represents a shift from empirical, field-based optimization to a molecularly guided, receptor-based design framework, advancing the development of enhanced male lure solutions for future applications in insect behavior manipulation.
Genetic Allee Effects for Controlling Invasive Populations
35313Louis Nowell Nicolle, Alex Fournier-Level, Charles Robin, et al., Molecular Ecology, 2026-01-02 10:37:23.
Invasive pests threaten food security and devastate ecosystems. A universal problem in their management is that small populations can easily evade detection. This makes identifying new incursions challenging and complicates efforts to eradicate or contain established populations. If newly founded populations exhibited a strong Allee effect, small populations would tend towards extinction and most new incursions would go extinct without the need for detection or intervention. Of course, invasive species rarely exhibit strong Allee effects, but new genetic technologies make it conceivable to impose one. Here we consider how introduction of genetic load can cause a genetic Allee effect that reduces the establishment probability of small founder populations. Using numerical and individual-based modelling, we examine the fate of populations sampled from a larger invasive source population carrying deleterious recessive alleles. Our analysis reveals that the genetic load unmasked by founding can dramatically reduce the establishment probability of small populations across a wide range of parameter space. A sterile mutation effect is more effective than a lethal mutation effect, but X-linkage offers minimal benefit over autosomal inheritance. Although extinction of newly founded populations is a common outcome, it may be challenging to achieve in species with very high reproductive outputs. Distributing deleterious recessive alleles across a large number of loci at low frequencies was more effective than distributing them across fewer loci at higher frequencies. Our findings suggest that driving deleterious recessives into a source population may render it less prone to establish in new areas.
Strategies to improve the efficiency of homing gene drives with multiplexed gRNAs
35416Chen, W., Wu, P. & Champer, J., BMC Biol, 24. 2025-12-12 16:50:27.
CRISPR homing gene drive holds great potential for pest control, but its success is challenged by the generation of resistance alleles through end-joining repair. Using multiple gRNAs to target adjacent sites within a conserved gene can prevent functional resistance by allowing repeated cleavage events, but poor homology during DNA repair may compromise efficiency. We first assessed the efficiency of single gRNA drives with truncated homology arms in Drosophila melanogaster mimicking a multiplexed system in which only one site is cleaved. Integrating results into a detailed gRNA multiplexing model, we found that efficiency loss was greater than expected. To mitigate this, we evaluated two new strategies: (1) extended homology arms to span all target sites (with mutations in the PAMs to prevent self-cleavage) and (2) a population-level gRNA multiplexing system involving two or more drives, each carrying two gRNAs. Extended homology arms did not result in notable improvement in conversion efficiency, and the extended region could be lost during drive conversion. The population-level multiplexing gRNAs strategy was more promising, though the intentionally mutated PAM also could not be consistently inherited. Simulations of homing suppression drives applying population-level multiplexed gRNAs increased the success rate of population elimination and reduced the time required for suppression. Future drive designs requiring a larger number of gRNAs could potentially be improved. The design relying on extended homology arms may not represent an optimal strategy. However, population-level multiplexing gRNAs could serve as a promising alternative, enhancing efficiency while maintaining tolerance to functional resistance.
Homing gene drive strains for genetic suppression of agricultural insect pests
35331Yadav, Amarish K.; Tarrand, Ariel E.; Scott, Maxwell J., Entomologia Generalis, 45:1577 - 1590. 2025-12-04 14:52:03.
Agricultural insect pests cause substantial losses in crop productivity each year. Genetic-based strategies provide economical and environmentally friendly ways to limit pests that reproduce sexually. In contrast to conventional genetic methods (e.g. SIT), homing gene drives (HGDs) are potentially capable of suppressing or modifying an entire pest population in a short period of time after releasing a small number of HGD insects. The advent of CRISPR/Cas gene editing tools has simplified the engineering of gene drives, and the progress made on HGDs in various insects in the recent past is encouraging. However, to date HGDs have been developed and evaluated in only a few agricultural pest species. These drives have been designed to suppress populations by targeting genes essential for female development or fertility. Homing gene drive relies on homology directed repair (HDR) of the Cas9-mediated double-stranded DNA break in germ cells. Consequently, the use of other DNA repair pathways such as non-homologous end joining (NHEJ) and micro-homology mediated end joining (MMEJ) can retard homing. Further, establishment of functional resistant alleles through these end-joining pathways is one of the major challenges associated with HGDs. Development of HGDs in some pest species is challenging due to the technical difficulties of making transgenics. Identification and characterization of germline-specific promoters and other regulatory elements to achieve precise HDR (in early meiosis) can facilitate efficient homing. In this review, we highlight the recent progress made towards developing HGDs in agricultural insect pests with insights gained from studies in model organisms (e.g. Drosophila melanogaster).
SIT-ia: A Software-Hardware System to Improve Male Sorting Efficacy for the Sterile Insect Technique
35267de la Vega, G., Smith, L., Soria-Mercier, L., et al., Insects, 16. 2025-11-02 17:34:18.
This research addresses a challenge in using the Sterile Insect Technique (SIT), an eco-friendly pest control method. For SIT to work, only sterile male insects can be released, but sorting males from females by hand is slow and laborious. The study introduces a new automated system called SIT-ia that uses artificial intelligence (AI) to quickly and accurately tell male and female flies apart. When tested on the spotted-wing drosophila (Drosophila suzukii), the system was 98.6% accurate. A key benefit is its speed: SIT-ia can sort 1000 flies in about 70 min, which is 40 min faster than human experts. This innovation makes sex-sorting a more efficient and practical process, needed for managing pest insects in a sustainable way. Invasive insects can cause significant economic impacts to agriculture worldwide and impact human health. Traditional pest management methods that include chemical insecticides have raised increasing environmental and health concerns, prompting the need for sustainable alternatives. The Sterile Insect Technique (SIT), which consists of releasing sterile males of a target pest to mate with wild females, is held as a promising solution. However, the success of SIT relies on the release of sterile males. The efficient separation of sexes prior to sterilization and release is necessary. This study presents SIT-ia, a software–hardware system that utilizes artificial intelligence (AI) and computer vision to automate the sex-sorting process. We showcase its use with the fruit fly pest D. suzukii. The system was able to identify males from females with a 98.6% accuracy, sorting 1000 sterile flies in ~70 min, which is nearly half the time involved in manual sorting by experts (i.e., ~112 min). This simple device can easily be adopted in SIT production protocols, improving the feasibility and efficacy of improved pest management practices.
Selection, counterselection, and conditional gene expression for genetic biocontrol of insects
35249Melanie Hempel, Zhijian Tu, Insect Science, 2025-10-16 09:29:04.
Genetic biocontrol methods are species-specific ways to suppress or modify pest insect populations to mitigate their economic or health impact. Successful genetic biocontrol often requires mass releases of only males of the target species. Reliable and cost-effective sex separation is a major bottleneck to the implementation of genetic biocontrol of many important species of agricultural and medical importance. Conditional selection is critical to resolving this major challenge. A diverse array of tools, such as the temperature-sensitive systems, the Gal4/UAS, QF/QUAS, and Tet-on/off bipartite systems, and the photoactivatable systems, have been established in various insect species. In this review, we focus on how various means of conditional expression have been used to achieve sex separation. We also describe other means of selection and counterselection to achieve sex separation without conditional gene expression. By providing examples across many species and discussing the strengths and weaknesses of each method, we hope to facilitate the design and application of conditional systems to improve genetic biocontrol of insect pests.
Cattle Q&A with Brinda Dass, GeneConvene Global Collaborative
35243Tyrell Marchant, Progressive Cattle, 2025-10-15 08:41:35.
What factors have led to the northward spread of New World screwworm (NWS) over the past year after so many decades of successful eradication in Mexico and the U.S.? DASS: The northward spread of NWS after decades of eradication reflects a convergence of biological, environmental and programmatic factors. Climate change and increasing temperatures have created favorable conditions for pupal survival and year-round reproduction, enabling rapid reinvasion from subtropical regions. NWS biology – especially females’ ability to lay multiple waves of eggs in wounds – allows populations to surge quickly even from small footholds. High-density livestock practices and insufficient inspection of animal trade further accelerate spread, with smuggling through the Darién Gap undermining surveillance. Wildlife, pets and humans act as reservoirs, compounding detection challenges. Sterile insect technique (SIT), historically successful, has been overwhelmed: Production of sterile flies cannot match population growth, forcing control lines northward. Budget constraints, political disputes and reduced funding have further weakened monitoring and response systems. Together, these dynamics explain how a long-maintained eradication barrier collapsed, allowing NWS to expand northward at alarming speed.
Exploring experts’ uncertainties about gene drive technology for agricultural pest control in the U.S.: a qualitative study to inform innovation and decision-making
35241Barry, N., Barnhill, S.K. & Johnson, B.B., Environment Systems and Decisions, 45. 2025-10-15 08:34:10.
As experts consider what it might look like for gene drives to manage agricultural pests, there remain several uncertainties across a broad range of issues, including technical, ecological, regulatory, and social implications. Drawing on 25 expert interviews, we parse out these uncertainties and the potential for Adaptive Management to help guide development, deployment, and governance of gene drives for invasive agricultural pest management. Adaptive Management emerged specifically to attend to uncertainties in complex social-ecological systems, prescribing collective learning and responsiveness to stakeholder feedback to effectively reach management goals. Thus, Adaptive Management provides clear direction on how to account for and make decisions in the face of considerable uncertainties surrounding these gene drive tools. We also give some attention to the ways in which the uncertainties that are specific to agricultural applications are somewhat distinct from or consistent with global discourse around gene drive development across sectors.
Improvement of colony management in insect mass-rearing for sterile insect technique applications
35183Adly M.M. Abd-Alla, Anne Geiger, David Haymer, Insect Science, 2025-09-29 08:40:15.
Sterile Insect Technique (SIT) applications against major insect pests and disease vectors rely on the cost-effective production of high-quality sterile males. This largely depends on the optimal management of target pest colonies by maximizing the benefits provided by a genetically rich and pathogen-free mother colony, the presence of symbiotic microorganisms, and efficient domestication, mass-rearing, irradiation, and release processes. At the same time microbial (bacteria, fungi, microsporidia, and viruses) pathogen outbreaks should be minimized or eliminated, and the use of hazardous chemicals restricted. The optimization of the colony management strategies for different SIT target insects will ensure a standardized high-quality mass-rearing process and the cost-effective production of sterile males with enhanced field performance and male mating competitiveness. The aims of the Coordinated Research Project (CRP) were to develop best practices for insect colony management for the cost-effective production of high-quality sterile males for SIT applications against major insect pests and disease vectors through a multidisciplinary approach involving entomologists, geneticists, ecologists, microbiologists, pathologists, virologists, and mass-rearing experts.
Development and evaluation of pupal color-based genetic sexing strains in Anastrepha obliqua
35116Daisy P. Cárdenas-Enríquez, Víctor García-Martínez, Jorge Ibáñez-Palacios, et al., Insect Science, 2025-09-08 08:23:07.
Anastrepha obliqua, a neotropical pest widely distributed in the Americas, attacks mango and other tropical fruits. In Mexico, it is controlled through integrated pest management, using the Sterile Insect Technique (SIT) as a main component. The applicability of SIT is significantly improved with the use of genetic sexing strains (GSS) that allow the possibility to release exclusively sterile males, the primary component of the technique. This study reports the isolation and characterization of two pupal mutations: black pupae (bp) and sphere pupae (sp), allowing for the first time the development of a genetic sexing system based on pupal color in this species. Inheritance analyses from reciprocal crosses between wild-type and mutant individuals showed F2 phenotypic segregation consistent with a recessive Mendelian inheritance pattern, and linkage analysis indicated that the bp and sp loci are in separate chromosomes. Using the bp mutation, two GSS were developed through gamma irradiation [T(Y;bp+)/bp-22](GSS-22) and ethyl methanesulfonate treatment [T(Y;bp+)/bp-354](GSS-354). Both GSS exhibited sex-specific pupal differentiation but displayed a high frequency of recombinants. Despite an initial reduction in biological fitness, GSS-22 demonstrated greater genetic stability and a lower frequency of recombinants than GSS-354. Discrepancies between cytogenetic and genomic data, particularly regarding the localization of the gene responsible for the black pupae phenotype, underscore the need to integrate polytene chromosome and genomic analyses to characterize these translocations and improve GSS stability precisely. These results represent a breakthrough in the creation of genetic tools for the management of A. obliqua control.
Autosomally-encoded segregation distortion of sex chromosomes
35096Greenberg Naomi L., Patten Manus M. and Schenkel Martijn A., Proc. R. Soc. B., 292. 2025-09-01 19:48:42.
Some selfish genetic elements drive at meiosis to achieve transmission distortion, breaking the rules of Mendelian segregation to enhance their own evolutionary success. It has been shown that enhancers of drive must act in cis in order to gain the selfish benefit of drive and that suppressors of drive will be selected at unlinked loci. Here, we model the evolution of an autosomal trans-acting gene (Distorter) that causes the Y chromosome (or even 0 chromosome) to drive without driving itself, a phenomenon we call ‘remote-control meiotic drive’. We show that such a gene may spread in the population when linked to a second locus, Assister, whose alleles are transmitted at different frequencies through sperm as compared to eggs, for which we consider various scenarios, such as sexually antagonistic selection or sex-limited drive. Depending on the mechanistic details of sex-chromosome drive, Distorter’s spread can additionally facilitate transitions between XY and X0 sex determination. Our results provide a proof of principle that stretches the current understanding of segregation modifier and sex allocation theory. Moreover, we identify alternative evolutionary trajectories that could also lead to remote control drive and discuss its potential applications in developing synthetic sex-ratio-distorting elements for use in pest management, for example.
The shibirets4 mutation causes temperature sensitive paralytic and lethal phenotypes in the Queensland fruit fly, Bactrocera tryoni
35094Anzu Okada, Mamoru Okamoto, Thu N.M. Nguyen, et al., Insect Science, 2025-09-01 19:43:43.
Bactrocera tryoni, the Queensland fruit fly, is among the most damaging insect pests to the Australian horticultural industry as larvae infest ripening fruits or vegetables prior to harvest. Genetic biocontrol using Sterile Insect Technique (SIT) programs have been used to successfully suppress populations, via mass release of factory-reared sterile males that mate with wild females. Bi-sex flies are currently used for releases, although the efficiency of these control programs could be improved through using genetic sexing strains that eliminate females early during development, as they are not required for SIT. Here we used CRISPR/Cas9 mutagenesis to modify two nucleotides in the B. tryoni gene shibire, which created a proline to serine amino acid substitution and produced a temperature sensitive phenotype. Shibire is an essential GTPase required in endocytosis and synaptic vesicle recycling, and classical mutagenic screens in the vinegar fly Drosophila melanogaster previously identified temperature sensitive alleles including shits4 that results in adult paralysis. In B. tryoni, the shits4 mutant strain exhibited similar adult paralytic phenotypes when exposed to high temperatures, as well as temperature dependent lethality at egg, larval and pupal stages when subjected to heat treatment above standard rearing temperatures. These temperature sensitive phenotypes could be adapted to develop a SIT genetic sexing strain for conditional elimination of females prior to sterile releases, to improve efficiency and reduce costs.
Field Performance of a Self-Limiting, Genetically Engineered Fall Armyworm for Biological Pest Management
35180Reavey Catherine E. , Domingues Felipe A. , Ercit Kyla, et al., Sec. Pest Management, 7. 2025-08-21 14:28:43.
The fall armyworm is one of the most globally significant agricultural pests, damaging corn, sorghum and other crops central to food production. It has developed resistance to several classes of chemical insecticides and, more recently, insect-resistant ‘Bt’ biotech corn varieties. As Bt varieties constitute the great majority of corn acreage in Brazil, proactive resistance management strategies are required to protect the durability of insecticidal efficacy of those cultivars. Previously, we reported on the development of a ‘self-limiting’ fall armyworm strain, called OX5382G, which – after release in the field – is engineered to suppress populations of fall armyworm and manage resistance to Bt crops in treated populations of this pest. Here, we build on this work by carrying out contained studies to empirically assess the pest suppression and resistance management benefits of releasing OX5382G males. We also report on the first open field releases of the OX5382G self-limiting strain in Brazil. Following commercial biosafety approval of this strain by Brazilian government regulators, deployment-relevant OX5382G male performance was then assessed in larger, operational trials in Brazil. Pest suppression and resistance management benefits were demonstrated in contained studies. In the first open field releases, OX5382G males showed comparable performance with wild-type counterparts in terms of dispersal and mating ability. In the subsequent larger, farm-scale trials in Brazil, OX5382G mated effectively in the field and we demonstrated that relatively modest release rates can achieve over-flooding ratios expected to exert suppression and/or resistance management. All assessments to date suggest that self-limiting fall armyworm is a promising future tool for managing fall armyworm and extending the durability of Bt crops’ effectiveness against damaging lepidopteran pests.
Novel stressors and trait variation determine X-linked meiotic drive frequency
35021Fisher Adam M., White Nicola, Bonsall Michael B., Price Tom AR. and Knell Robert J., Proc. R. Soc. B., 292. 2025-08-13 16:09:01.
Sex ratio meiotic drive alleles bias their transmission by impairing the viability of non-drive gametes, leading to skewed population sex ratios. Despite theoretical predictions that drive alleles should reach fixation causing population extinction, meiotic drive persists at intermediate frequencies in wild populations, though the reasons for this are unclear. Here, we investigate how novel environmental stress and genotype-specific fitness costs contribute to drive frequency. Using a suppression-free X-linked meiotic drive system in Drosophila pseudoobscura, we exposed flies to varying doses of the pesticide permethrin and measured mortality and fecundity across genotypes. We found that drive-bearing males (SR) and drive-homozygous females (SRSR) exhibited heightened mortality, both in the presence and absence of pesticide, while heterozygous (SRST) females exhibited superior fecundity. Using a mathematical model parametrized with our empirical findings, we explored the long-term population dynamics of meiotic drive under different conditions. Our model predicts that drive frequency has a concave relationship with pesticide dose and is strongly modulated by genotype-specific female fecundity. These results suggest that novel environmental stressors and drive-induced fitness effects play key roles in determining meiotic drive frequencies. Our findings improve our understanding of drive frequencies in the wild and have direct implications for drive-based pest control.
Genome Editing in Insect Pest Control: Importance, Strategies, and Future Implications
35011Ipsita Samal, Tanmaya Kumar Bhoi, Deepak Kumar Mahanta, Ansh Raj, J. Komal, Alagesan Keerthana, Vinod Kumar Dubey, Genome Editing for Pest Management, 2025-08-06 11:45:12.
Genome editing is a cutting-edge tool in biotechnology which brought about substantial changes in a variety of areas, including agriculture and pest control. As properly managing insect pests is critical for protecting food supplies and ensuring produce security, insect species frequently cause severe problems by destroying crop production, resulting in significant financial losses, food scarcity, and insufficiency. Innovative breakthroughs in pest management technology have lately resulted in the replacement of traditional chemical pesticide applications with environmentally safe and non-polluting interventions. Genome editing has the potential to transform pest control by providing precise and targeted therapies for insect pests that can be managed permanently. Researchers have discovered that genome editing methods have created new possibilities for improving food safety, agricultural productivity, and sustainable agriculture affected by pests. Scientists may now offset insect-related shortcomings with creative ways and strategies that ensure environmentally friendly and sustainable farming practices and environmental preservation, thanks to the application of genome editing tools. This chapter focuses on the use of these state-of-the-art technologies in genome editing tools such as ZFN, TALEN, and CRISPR/Cas9 enables us to assess the viability of insect control strategies, that provide significant promise for next-generation approaches to several major pest management problems and allow the insertion of precisely tailored modifications into the genetic composition of pests. To fully utilize the technology and specifically its implications for more efficient management of insect pests, study, analysis, and collaboration across many sectors are essential, which has been centralized in the current chapter.
Millions of genetically modified insects have been released in Brazil, but why didn’t anyone tell you about this before?
35003Noel Budeguer, Click Petroleo e Gas, 2025-08-04 08:29:56.
Few people realize, but Brazil is one of the most advanced countries in the world when it comes to biological pest control. Instead of relying solely on poisons and traps, Brazilian researchers are investing in technological solutions that, at first glance, seem like the stuff of science fiction: releasing modified mosquitoes and flies into the environment to prevent disease outbreaks and agricultural losses. The initiative may sound controversial, but it has already yielded impressive results—and, in some cases, may have prevented entire epidemics without anyone noticing. The logic behind these techniques is simple yet powerful. By releasing sterile or genetically modified males into the environment, they compete with natural males for females. When they win this contest and mate, the offspring born don't survive—or even hatch at all. The result is a drastic decline in the target pest's population. Two main approaches are used: the Sterile Insect Technique (SIT), which uses radiation to sterilize males, and genetic modification, which prevents reproduction through DNA alterations. Both methods eliminate the use of pesticides and have gained traction as sustainable and highly effective alternatives.
Decoding and engineering temperature-sensitive lethality in Ceratitis capitata for pest control
34970R.A. Aumann, G. Gouvi, M. Gregoriou,T. Rehling, G. Sollazzo, K. Bourtzis, and M.F. Schetelig, Proceedings of the National Academy of Sciences, 122. 2025-07-10 10:38:52.
The Sterile Insect Technique (SIT) is a species-specific and environmentally friendly method for effectively controlling pest insect populations based on releasing reared, sterile insects into infested areas. Sex sorting in rearing facilities, enabling male-only releases, is necessary to ensure SIT programs are efficient, cost-effective and, in case of mosquito control, also safe. This can be greatly facilitated by genetic sexing strains (GSS), exhibiting sex-specific phenotypic markers. However, the development of GSS remains challenging. The construction of a temperature-sensitive lethal (tsl)-based GSS in the Mediterranean fruit fly (Ceratitis capitata) over three decades ago was considered a major breakthrough for SIT programs but was never successfully replicated in other pests. After over 30 y of research, we have pinpointed a specific mutation in the C. capitata lysine--tRNA ligase (Lysyl-tRNA synthetase, LysRS) gene responsible for the tsl phenotype. Introducing this specific mutation into a wild-type strain produced full embryonic lethality under heat stress, replicating the original mutant phenotype. The random integration of a LysRS minigene reversed this effect. The high conservation of LysRS among insects suggests that tsl-based GSS could be expanded to multiple pest species and extend applications of SIT programs for disease prevention and the protection of agriculture.
Genetic discovery advances insect pest control worldwide
34968IAEA, Phys.org, 2025-07-09 10:29:16.
An international research team led by Justus Liebig University Giessen (JLU) and the Joint FAO/IAEA Center of Nuclear Techniques in Food and Agriculture has identified the gene responsible for a temperature-sensitive lethality (tsl) phenotype in the Mediterranean fruit fly, solving a long-standing mystery. Their research is published in the Proceedings of the National Academy of Sciences. The sterile insect technique (SIT) involves the mass-rearing and sterilization using radiation of a target pest. Sterile males are then released over defined areas, where they mate with wild females, producing no offspring, which reduces the pest population. The SIT dates back to 1916, when scientists first used X-rays to induce sterility in insects. It was successfully implemented in the 1950s against the New World screwworm in the United States of America. Since then, SIT has become a globally recognized and target-specific method to suppress invasive and established insect populations of agriculture, veterinary and medical importance. The effectiveness and efficiency of SIT depends on reliably separating the sexes so that only sterile males are released in the field. A breakthrough came in the late 1980s with the discovery of the tsl mutation at the Joint FAO/IAEA Center's Insect Pest Control Laboratory. This was followed by the development of tsl-based genetic sexing in Ceratitis capitata, in which female offspring die at the embryonic stage following short-term heat treatment. This made it possible to produce sterile male flies at an industrial scale. Yet the gene underlying this effect remained unidentified for more than three decades, limiting the broader application of this approach to other insect species.
Synthetically Assisted Conservation and the Application of Emerging Biological Technologies for the Protection of Biodiversity
34956Jedediah F. Brodie, Amanda Emmel, Blake Wiedenheft, et al., Conservation Letters, 8. 2025-07-08 13:20:29.
New tools of synthetic biology that enable precise manipulation of genomes, metabolic pathways, and ecosystems present new opportunities, risks, ethical dilemmas, and responsibilities for stewards of biodiversity. We argue that the risks and benefits of synthetic biology for use in biodiversity conservation, which we term “synthetically assisted conservation,” can be better understood, evaluated, and regulated by precisely defining the techniques in relation to well-established and regulated conservation frameworks: conservation translocation and integrated pest management. Synthetically assisted conservation translocation could include the release of genetically modified organisms for in situ conservation of genes or restoration of ecological functions, while a synthetically assisted application of integrated pest management could involve using genetic modifications propagated through gene drives to remove invasive species. Contextualizing the range of techniques as expansions of these frameworks clarifies how new approaches may impact conservation, facilitating risk assessment and responsible implementation. Decision-making may be informed by existing policy guidance in accordance with national and international regulations on conservation translocation and integrated pest management. Nevertheless, additional policy and evaluative guidelines are needed to keep pace with rapid technological growth and novel issues such as the release of genes (e.g., in pollen or marine-dispersed gametes) separate from live organisms.
Rollins presses ahead with latest initiative on New World screwworm
34924HPJ staff, High Plains Journal, 2025-06-19 14:41:39.
U.S. Secretary of Agriculture Brooke Rollins on June 18 announced an $8.5 million sterile New World screwworm fly dispersal facility in south Texas and a five-pronged plan to enhance the U.S. Department of Agriculture’s ability to detect, control and eliminate the pest. In a media release, the USDA noted actions are necessary to finish the fight against NWS and protect the United States. NWS is a devastating pest that causes serious and often deadly damage to livestock, wildlife, pets, and in rare cases, humans. While NWS has been eradicated from the U.S. for decades, recent detections in Mexico as far north as Oaxaca and Veracruz, about 700 miles away from the U.S. border, led to the immediate suspension of live cattle, horse and bison imports through U.S. ports of entry along the southern border on May 11. “The United States has defeated NWS before and we will do it again,” Rollins said. “We do not take lightly the threat NWS poses to our livestock industry, our economy, and our food supply chain. The United States government will use all resources at its disposal to push back NWS, and today’s announcement of a domestic strategy to bolster our border defenses is just the beginning. We have the proven tools, strong domestic and international partnerships, and the grit needed to win this battle.”
Efficient CRISPR-Cas9-mediated genome editing of the cane toad (Rhinella marina)
34887Michael Clark, Alexander T. Funk, Alex Paporakis, et al., bioRxiv, 2025-06-02 19:02:13.
Invasive species inflict major ecological, economic, social, and cultural harm worldwide, highlighting the urgent need for innovative and effective control strategies. Genome editing offers exciting possibilities for creating highly targeted control methods for invasive species. Here, we demonstrate CRISPR-Cas9 genome editing in the cane toad (Rhinella marina), one of Australia’s most notorious invasive species, by targeting the tyrosinase gene to produce albino phenotypes that provide clear visual markers for assessing editing efficiency. Microinjection of Cas9 protein and guide RNAs into one-cell zygotes resulted in 87.6% of mosaic larvae displaying nearly complete albinism, with 2.3% exhibiting complete albinism. For completely albino individuals, genomic analysis confirmed predominantly frameshift mutations or large deletions at the target site, with no wild-type alleles detected. Germline transmission rates reflected the extent of albinism in the mosaic adult, where we achieved maternal germline transmission rates of almost 100%. This technology, representing the first application of CRISPR-Cas9 in the Bufonidae family, opens possibilities for exploring both basic research questions and strategies for population control.
Should we wipe out the pests now that we can?
34885Miguel Ángel Criado, El Pais, 2025-06-02 18:47:38.
Felicola (Lorisicola) isidoroi is a creature that is probably either extinct or on the verge of being so. In the past, it must have been present throughout most of the Iberian Peninsula, but the last time scientists encountered one was in 1997. For biologists, this represents a loss of biodiversity. For everyone else, it’s just another bug. Felicola (L.) isidoroi is a louse that lives by sucking blood. Its unique feature is that its only host is the Iberian lynx. Specific to the most endangered feline on the planet, it shared the latter’s path to extinction until humans decided to save the feline, but not its parasite. The lynx recovery program includes deworming specimens released in the wild, a procedure that is also conducted in the event of a capture. Jesús María Pérez, a zoologist and expert in pests and parasites at the University of Jaén in southern Spain, believes that the louse is still a much rarer species than the lynx itself, and should also be saved because it is part of biodiversity: “As a unique product of evolution, it has incalculable value.” The dilemma posed by the lynx louse is the same one generated by many other parasites, pests, and species that, like some mosquitoes, are not pathogens themselves but vectors that carry the cause of various diseases. A few days ago, a group of biologists, ecologists and sociologists published an opinion piece in the journal Science whose title makes it clear what it’s about: Deliberate extinction by genome modification: An ethical challenge.
Screwworm Fly: US Threat & Prevention
34883News Directory 3, 2025-06-02 18:43:27.
A resurgence of the New World screwworm, a parasite known for consuming living flesh, is raising alarms in the U.S.cattle industry. For seven decades, the United States has waged an aerial war against this pest, scientifically known as C.hominivorax, which targets livestock and even humans. The U.S.Department of Agriculture (USDA) pioneered a strategy in the 1950s involving the mass production, sterilization via radiation, and aerial release of sterile screwworms to disrupt the parasite’s reproduction cycle. This approach successfully created a barrier at the Darién Gap between Panama and Colombia, effectively shielding North America. However, in 2022, this barrier was breached. Panama saw a surge in screwworm cases, and by 2024, the parasite was rapidly advancing northward.It has now reached Oaxaca and Veracruz in Mexico, prompting the U.S. to suspend live-cattle imports from Mexico. Wayne Cockrell,a Texas rancher and chair of the cattle-health committee for the Texas and Southwestern Cattle Raisers Association, expressed concern about the potential return of the screwworm to Texas. He believes the current sterile-fly programme lacks the capacity to contain the outbreak.
Advances in Sterile Insect Technique Driven by Sugarcane Pest Management in South Africa
34852Lawrence N. Malinga, Ph.D., and Samara Singh, Entomology Today, 2025-05-26 20:21:30.
Eldana saccharina, also known as the African sugarcane stalk borer, is an insect pest indigenous to Africa that targets gramineous crops such as sugarcane, maize (corn), sorghum, and millet in several countries, including Zimbabwe, Mozambique, Ethiopia, Ghana, Nigeria, and others. In South Africa, E. saccharina is the most damaging pest of sugarcane. The larvae feed internally on plant tissue, leading to a significant reduction in sugarcane yield. In South Africa, this damage amounts to over $60 million in annual revenue losses. In 1939, the first severe outbreak of this pest was recorded on sugarcane in South Africa. Since then, E. saccharina has spread throughout the sugarcane-growing areas of South Africa, affecting both coastal and inland regions (see map). Since the 1970s, the South African Sugarcane Research Institute (SASRI) has been actively involved in conducting research to control this pest. Over the years, attempts have been made to manage E. saccharina using a variety of control tactics, including insecticides, varietal resistance, biological control, and habitat management. A more recent control strategy is the sterile insect technique (SIT), which is currently in the proof-of-concept phase at SASRI.
Mathematically modelling the population dynamics of CRISPR gene drive systems in the pine pest Sirex noctilio
34779Strydom, H., Ouifki, R., Chapwanya, M., bioRxiv, 2025-04-18 10:34:17.
Sirex noctilio is an invasive pest of pine that has caused significant economic damage in South Africa and many other Southern Hemisphere countries. Current management tools are not efficient in all cases and consequently there is a need for more efficient and targeted control measures. An emerging tool for pest management is the use of gene editing and associated gene drive systems. In this study, we aim to investigate the use of CRISPR-Cas gene drive systems in the management of S. noctilio in South Africa. As a first step, we developed a model for the population dynamics of S. noctilio, using historical national population monitoring data and incorporating the influence of two main biological control agents of the pest. We then modelled the influence of two different CRISPR-Cas systems on the population dynamics of S. noctilio namely, a baseline CRISPR model and Complementary Sex Determination CRISPR (CSD) model. Each model is used to simulate a male and female only introduction strategy to estimate the effectiveness of different methods of introducing the gene drive system. The model calibration was achieved by optimizing the model fit to existing data using the least squares technique. Results suggest that both CRISPR gene drive systems would be effective at controlling the population growth of S. noctilio at high levels of introduction, but overall population control would be hindered by practical limitations. Although only two CRISPR models were explored, the underlying population model serves as a framework for further studies into the population dynamics of Sirex noctilio, as well as many other CRISPR-Cas gene drive systems.
Engineering drive–selection balance for localized population suppression with neutral dynamics
34597Willis, K., and Burt, A., Proceedings of the National Academy of Sciences, 122. 2025-03-18 10:29:28.
While the release of sterile males has been highly successful in suppressing some pest populations, it is impractical for many species due to the males disappearing after a single generation, necessitating large, repeated releases to maintain sufficient impact. Synthetic gene drives promise more efficient approaches since they can increase in frequency from rare, yet this also allows them to spread across a landscape, which may not always be desired. Between these two extremes are selectively neutral genetic constructs which persist at the frequency they are released, offering the potential for efficient suppression that remains localized. One way to achieve this would be to have perfect balance, at all construct frequencies, between gene drive increasing frequency and selection decreasing it. Here, we describe a way to closely approximate this balance using a toxin–antidote genetic construct that causes recessive lethality or sterility, encodes a genomic editor that makes dominant lethal or sterile edits in the genome, and provides protection against the action or consequences of the editing. Computer modeling shows that this design can be 100-fold more efficient than sterile males, increasing to 1,000-fold when released alongside a genetic booster. We describe designs for CRISPR-based molecular construction, including options that avoid using recoded genes as antidotes.
Public attitudes to genetic technology for invasive pest control and preferences for engagement and information: a segmentation analysis
34499Hobman E.V., Mankad A., Carter, L., Collins K., Frontiers in Bioengineering and Biotechnology, 12. 2025-02-04 19:37:26.
Advances in genetic technology hold promise in managing the increasing problem of invasive pests. The current study sought to improve our understanding of public perceptions, and potential public engagement pathways and information needs as the technology is researched and potentially developed for deployment. A survey of 1,149 Australians was conducted, and the sample was segmented into 4 groups based on their attitudes: Certain Objectors, Fence Sitters, Cautious Supporters, and Certain Supporters. ‘Light touch’ engagement activities appeared to satisfy most people; yet more intensive engagements could be appropriate for a small group who hold negative views towards the technology. Across the board, people wanted to know about the potential risks, and the regulation and controls surrounding the gene editing technology. Those who held more positive views also showed an interest in the scientific processes and techniques, while people who held more negative views wanted to know what was being done to deal with social and ethical issues. The results provide insight into 1) the diversity of views, and associated beliefs and feelings, among the public when confronted with a synthetic biology solution to an environmental problem, 2) how public engagement activities can be tailored to align with people’s engagement beliefs and stated preferences, and 3) what issues biotechnology developers should address as they endeavour to design genetic technology in a socially responsible way.
Dissecting The Sterility Phenotype Of Drosophila Suzukii Males
34489Evrim Ağacı, The Pinnacle Gazette, 2025-02-04 17:43:46.
Groundbreaking findings on gene-edited males provide insights for pest management strategies. Researchers have made significant strides in controlling the invasive fruit pest Drosophila suzukii, commonly known as the spotted wing drosophila, utilizing innovative genetic engineering techniques to generate sterile males. This development could offer growers much-needed relief as traditional pest control methods face increasing challenges. Drosophila suzukii, native to East Asia, poses substantial threats to soft fruits, including strawberries and blueberries, by laying their eggs directly within the fruits, leading to damage and economic losses for farmers. With insecticide resistance on the rise and grower reliance on chemical management becoming less sustainable, there is urgent demand for novel pest control strategies. One promising approach is the precision-guided Sterile-Insect Technique (pgSIT), which employs CRISPR-based technology to develop sterile males efficiently. Unlike traditional Sterile-Insect Techniques, which involve labor-intensive processes like sex sorting and radiation to sterilize males, pgSIT simplifies the method and reduces costs by creating sterile males without offspring. The recent study, published on February 1, 2025, by researchers affiliated with Agragene Inc., aimed to dissect the sterility phenotype of these genetically modified males. It was found through multiple experiments and rigorous testing processes, including mating trials with wildtype females, determining the absence of mature sperm and the lack of genetic material transfer during mating.
Establishment of pupal color as a screening marker and activity analysis of six U6 promoters in Zeugodacus cucurbitae using the white pupae gene
34487Fan Z., Wu Y., Zha X., Ma S., et al., Pest Management Science, 2025-02-04 17:36:39.
The genetic control method, which is environmentally friendly and species-specific, has effectively reduced or eliminated pests in many areas. One essential requirement to control a species is the identification of its genetic and molecular elements. Such elements, however, are rarely available in Zeugodacus cucurbitae, a very destructive insect pest worldwide. In this study, we knocked out the white pupae (wp) gene in Z. cucurbitae and generated a wp(−) strain, which has a white pupae phenotype. The white puparium color was successfully restored to brown by inserting the wp gene rescue allele into the genome of the wp(−) strain using piggyBac transgenic technology. The potential wp promoter was then truncated to drive the expression of the wp gene and the puparium color was rescued even by the 605 bp sequence upstream of its transcription initiation site. Further fertility tests showed that knocking out or rescuing the wp gene had no effect on the reproduction of adult flies. In addition, we identified six U6 promoters and tested their promoter activities in the embryos of Z. cucurbitae. The ZcU6-2 and ZcU6-1 promoters exhibited significantly higher activity than the others and are suitable for use in CRISPR technology-based genetic control methods. Our work first shows the success of applying piggyBac transgenic technology in Z. cucurbitae. Our results demonstrate a highly efficient transgenic screening marker by puparium color and the promoter activity of multiple ZcU6 promoters, facilitating the construction of transgenic strains that are used for genetic control of tephritid species. © 2025 Society of Chemical Industry.
Biotechnology-enhanced genetic controls of the global pest Drosophila suzukii
33392Ying Yan, Hassan M.M. Ahmed, Ernst A. Wimmer, et al., Trends in Biotechnology, 2024-11-04 17:35:39.
Genetic control is a biological control method that introduces traits that sterilize, kill, or modify the population via intraspecific mating. Therefore, it is regarded as a species-specific and environmentally friendly management option for pest species. Spotted wing Drosophila (SWD) is an ideal insect model for studying genetic control strategies due to its pest status, laboratory-friendly biology, and close relationship to Drosophila melanogaster, which has abundant genetic resources. Different biotechnology-enhanced genetic control strategies of SWD are featured. The working schematics, control efficacies, some resistance mechanisms, and possible future development of these strategies are described. The designs and experience from these studies aid in the sustainable control of SWD and serve as essential references to other insect pests of economic or public health importance.
Pest control gets the CRISPR treatment
33376Seydel, C., Nature Biotechnology, 2024-11-04 13:45:02.
In June 2024, the St. Louis–based pest control company Agragene released genetically modified fruit flies on berry farms in California and Oregon, moving the technology out of the laboratory and into contained field testing. The trial marked a milestone for a next-generation biocontrol technology called the precision-guided sterile insect technique, or pgSIT. “The spotted wing drosophila (SWD) is the number 1 problem for any kind of strawberry, blueberry, raspberry, blackberry grower,” said Bryan Witherbee, president and CEO of Agragene. The flies have developed resistance to conventional chemical pesticides, and fruit growers suffer enormous economic losses due to the pest. “Growers are crying out for new tools,” Witherbee said. Hope is on the horizon, not only for farmers battling SWD and other agricultural pests but also for public health agencies struggling to control disease vectors. Several companies, including Agragene, are bringing biological pest control into the CRISPR era with pgSIT and other molecular tools that can specifically target the pest without killing beneficial insects, polluting the water or blanketing communities with toxic airborne chemicals. San Diego–based Synvect is applying pgSIT to disease-causing mosquitoes. Meanwhile, Oxitec, which has already successfully commercialized its “Friendly” genetic modification platform in mosquitoes, is turning its attention to crop pests.
Fluorescent-based sex-separation technique in major invasive crop pest, Drosophila suzukii
32544Junru Liu, Danny Rayes, Minzhe Yang, Omar S. Akbari, bioRxiv, 2024-10-09 12:30:05.
Insect population biocontrol methods such as the sterile insect technique (SIT), represent promising alternatives to traditional pesticide-based control applications. To use these strategies efficiently requires scalable sex separation techniques which are currently lacking in Drosophila suzukii, a prominent crop pest species. Having previously characterized a fluorescence-based sex-sorting technique in other pests, termed SEPARATOR (Sexing Element Produced by Alternative RNA-splicing of A Transgenic Observable Reporter), here we explore its potential applicability to Drosophila suzukii. Here, we engineer several strains of Drosophila suzukii encoding SEPARATOR constructs that allow for efficient sex selection in early larval stages.
Loss-of-function in testis-specific serine/threonine protein kinase triggers male infertility in an invasive moth
32506Wei, Z., Wang, Y., Zheng, K. et al., Communications Biology, 7. 2024-10-08 09:10:05.
Genetic biocontrol technologies present promising and eco-friendly strategies for the management of pest and insect-transmitted diseases. Although considerable advancements achieve in gene drive applications targeting mosquitoes, endeavors to combat agricultural pests have been somewhat restricted. Here, we identify that the testis-specific serine/threonine kinases (TSSKs) family is uniquely expressed in the testes of Cydia pomonella, a prominent global invasive species. We further generated male moths with disrupted the expression of TSSKs and those with TSSKs disrupted using RNA interference and CRISPR/Cas9 genetic editing techniques, resulting in significant disruptions in spermiogenesis, decreased sperm motility, and hindered development of eggs. Further explorations into the underlying post-transcriptional regulatory mechanisms reveales the involvement of lnc117962 as a competing endogenous RNA (ceRNA) for miR-3960, thereby regulating TSSKs. Notably, orchard trials demonstrates that the release of male strains can effectively suppress population growth. Our findings indicate that targeting TSSKs could serve as a feasible avenue for managing C. pomonella populations, offering significant insights and potential strategies for controlling invasive pests through genetic sterile insect technique (gSIT) technology.
Advancements and Future Prospects of CRISPR-Cas-Based Population Replacement Strategies in Insect Pest Management
31330Zhao Y, Li L, Wei L, Wang Y, Han Z., Insects, 15. 2024-09-03 18:39:10.
Many insects are categorized as agricultural pests due to their ability to transmit diseases and damage crops, which results in significant economic losses. Scientists have proposed two main pest control strategies: population suppression, aimed at reducing the size or distribution of pest populations, and population replacement, which involves introducing genetically modified populations to replace wild pests after an initial release. Typically, population replacement strategies use gene drive systems to spread beneficial traits throughout the target population. Current promising gene drive systems include homing endonuclease genes (HEGs), Wolbachia, maternal-effect dominant embryonic arrest (Medea), and newly adapted CRISPR/Cas genome editing systems. This review provides an overview of the recent advancements in population replacement, including insights into the development, testing, and safe implementation of CRISPR-Cas-based gene drive techniques from laboratory settings to field applications. It also discusses recent developments, identifies research gaps, and offers a comprehensive analysis of genetic control strategies for insect pests.
New genetic editing technique can modify wild populations with less risk
31062Macquarie University, Phys.org, 2024-08-14 09:44:13.
A new technique developed by researchers from Macquarie University and the California Institute of Technology could allow scientists to more safely alter the genetic makeup of wild populations. The study is published in the journal Nature Communications. The researchers have proposed a new technique that aims to address some of the regulatory challenges and public concerns associated with existing genetic modification methods. Lead author Dr. Maciej Maselko from Applied Biosciences at Macquarie University says the technique, called an Allele Sail, would allow beneficial genetic changes to spread through a population without leaving "foreign DNA" behind. "Allele Sail offers a way to change the traits and fates of wild populations in ways that may be more acceptable, as the genetically modified part is introduced at low frequencies and usually won't last forever," he says. Genetic engineering could address major global challenges by altering the genetic makeup of certain wild populations—for example, to combat mosquito-borne illnesses such as malaria, or stop the spread of environmentally harmful invasive pests like cane toads. But there is genuine public concern about introducing genetic modification into wild populations, and many regulatory constraints. People are worried that modified organisms could contain foreign DNA that cause unpredictable ecological consequences over time; they worry that engineered genes could spread to other species with unknown impacts on ecosystems; and they also fear that once genetic modifications are introduced, they may not be able to be reversed. Traditional methods of genetic modification can also see a rapid spread of engineered genes within a population, raising both ecological and ethical questions. In response, many regulatory frameworks have been introduced to address genetic modification, presenting further challenges.
How to Use Genetic Biocontrol to Manage Insect Pests
29891Scientific Animations Without Borders, YouTube, 2024-05-07 16:41:35.
Pest insects often transmit disease to humans and animals and destroy crops. Controlling these pests can improve human health and increase agricultural production. Pest insects are often controlled by releasing other insects into the environment that will specifically kill the pests. This method of pest control is called biological control and is environmentally friendly because it reduces reliance on chemical insecticides and targets only the pest insects. Genetic biocontrol is a type of biological control where the released insects are the same species as the pest but with critical genetic differences and traits that affect their reproduction or lifespan.
Protecting the peppers: Unlocking the potential of the sterile insect technique
28989Society of Chemical Industry, Phys.org, 2024-03-11 10:00:52.
For the first time, researchers in Canada have investigated the use of the sterile insect technique for controlling populations of the pepper weevil, Anthonomus eugenii, an economically significant crop pest in North America. The paper, published in Pest Management Science, revealed compelling findings on the use of gamma irradiation as a sterilization technique to improve the sustainability and effectiveness of pepper weevil management worldwide. The study was a collaboration between Bruce Power, Nordion Inc., the University of Guelph, Agriculture and Agri-Food Canada, and the Fruit and Vegetable Growers of Canada. A. eugenii poses a significant challenge to pepper growers across much of North America, causing millions of dollars worth of crop damage annually. The beetle larvae damage the flowers and immature fruit of capsicum plants, with infestations causing yield losses of up to 90%. Managing A. eugenii populations is particularly challenging as the development of beetle larvae takes place in the protective confines of pepper fruits. Roselyne Labbe, Greenhouse Entomologist at Agriculture and Agri-Food, Canada, and corresponding author of the study, explained the challenges in identifying effective strategies to manage populations of A. eugenii. "In prior research, we found that few conventional, reduced-risk, or microbial pesticides could effectively knock down adult populations of the pepper weevil on greenhouse pepper crops."
Revolutionizing Livestock Biosecurity: Using CRISPR Technology to Combat the New World Screwworm
28963Dr. Jessica Nelson, Medriva, 2024-03-05 13:07:55.
The New World screwworm, a persistent parasite responsible for significant damage to the global livestock industry, may soon meet its match. Researchers at Uruguay's National Institute of Agricultural Research (INIA) have developed a gene drive using CRISPR technology to combat this destructive pest. By manipulating the reproductive process of the screwworm fly, INIA scientists aim to cause a population crash, thereby reducing the parasite's devastating impact on the livestock industry. CRISPR gene drive technology offers a potentially more efficient and powerful solution compared to previous methods, such as the sterile insect technique (SIT) used by the US. Unlike traditional techniques, CRISPR gene drives aim to spread fertility-damaging genes throughout the screwworm population, causing a significant decrease in their numbers. The process works by making female screwworms sterile. The ultimate goal is to release gene-edited male screwworm flies into the wild. These males will mate with females, passing on the gene drive and leading to a population crash of the screwworm fly. This innovative approach has shown promise in caged trials and is currently being tested further in the INIA labs.
Uruguay wants to use gene drives to eradicate devastating screwworms
28961Abdullahi Tsanni, MIT Technology Review, 2024-03-05 12:53:17.
On a warm, sunny day in Montevideo, Uruguay, the air is smogless and crisp. Inside a highly secured facility at the National Institute of Agricultural Research (INIA) are a sophisticated gene gun, giant microscopes, and tens of thousands of gene-edited flies, their bright blue wings fluttering against the walls of their small, white, netted cages. These flies—shown to me on video by an INIA veterinarian, Alejo Menchaca—are a new weapon that may soon be unleashed against an enemy that kills cattle and costs the livestock industry millions of dollars every year: the New World screwworm, a parasite common in parts of South America and the Caribbean. When a female screwworm fly attacks cattle, it lays eggs, which hatch and turn into worm-like larvae that screw down into the host animal, feeding on flesh along their way and damaging the animal’s skin. Left untreated, the animals eventually die in excruciating agony. But Menchaca and colleagues have a plan. Using the genome-editing system CRISPR, they’ve developed what’s known as a gene drive, a type of genetic element that manipulates the reproductive process to spread farther and faster than an ordinary gene. They are about to move into the next stage of caged trials in the lab, with a view to eventually using the genetic tool to decimate the screwworm fly population. In collaboration with Institut Pasteur de Montevideo, they have received a $450,000 grant from the Inter-American Development Bank (IDB) for the research.
Revolutionary Gene Drive Could Provide Solution for Agricultural Pest Control
28877María Alejandra Trujillo, Breaking News Network, 2024-02-13 17:35:22.
The crux of the gene drive hinges on the process of sex determination in medflies. The drive effectively converts genetic females into fertile XX males, which, unlike their female counterparts, are harmless to crops. This innovative approach presents a possibility for a more environmentally friendly and cost-effective strategy to control agricultural pests—particularly those within the same group as medflies. The study was helmed by Dr. Nikolai Windbichler and Dr. Angela Meccariello of Imperial's Department of Life Sciences. Their work adds to the progressive field of gene drives, a concept that has demonstrated efficacy in laboratory settings, especially with regards to controlling populations of malaria-carrying mosquitoes. However, no gene drives have yet been released into the wild. The success of this proof-of-concept study stands as a testament to the potential of gene drives as a tool to manage agricultural pests. Dr. Meccariello, co-leader of the research, emphasized the untapped potential of gene drives in tackling pest problems in agriculture. She believes that this breakthrough could open the door to a more sustainable and economical approach to pest control.
The $11million wasp to end (hopefully) all wasps
28867Kieran Chisnall, Stuff, 2024-01-30 20:07:32.
A new project to eradicate wasps, which cost the country millions of dollars, has begun in Dunedin. The key to that $11million project would be a genetically altered wasp, capable of destroying wasps colonies from the inside. Professor Peter Dearden, Genomics Aotearoa co-director, said: “We are using this as a test case for all New Zealand pests, a prototype for what can be done in the most ethical way, the safest way, and the way that follows the science. “What we want is to develop research to make this firstly, scientifically possible, and secondly, offer a blueprint for how it can be done, if and when New Zealand decides we want to do it.” The nationwide research led by Genomics Aotearoa began with the opening of new labs in Dunedin this week. It will be in that controlled environment where researchers will make the transgenic organism - a wasp that has been genetically modified with a flaw.
Gene editing would be helpful for pest control, report says
28836Alex Binkley, National Newswatch, 2024-01-23 18:28:10.
Ottawa-Canada needs to boost its gene editing research capacity to better advance that branch of science’s pest control potential, says a report by the Council of Canadian Academies. There is insufficient intensive research and development activity in gene-edited pest control in the country even though research capacity in related field exists, the report said. “Better alignment among Canada’s main public research funders is needed to develop the necessary personnel, and channel the correct expertise toward responsible technology development.” Gene editing research elsewhere is rapidly evolving and “contributes to an increasing variety of prospective mechanisms of action in genetic pest control, across numerous species.” Climate change will make pest issues more complex due to its potential impacts on ecosystems. That makes a risk assessment process central to decision-making in pest control that can be used to obtain valuable stakeholder and other input for prioritizing which technologies should be supported, the report said.
Sex or poison? Genetic pest management in the 21st century
28782Luke Alphey, BMC Biology, 21:289. 2024-01-11 13:14:20.
Pests do enormous damage to human and animal health, to agriculture and to biodiversity, with mosquitoes transmitting pathogens, insect larvae eating crops or invasive rodents threatening the last island refuges of endangered birds. This commentary focuses on insects, particularly mosquitoes. However, most considerations apply equally to other pest species. Genetic pest management (GPM) is the use of genetics to control pests through mating of modified pests with their wildtype counterparts. This allows heritable traits to be transferred (“introgressed”) into the wild pest population. In principle, any sexually reproducing pest species can be targeted. The aim is to reduce harm done by the pest population, with typical intended outcomes overwhelmingly falling into two types: population suppression and population modification. For population suppression, one would introgress fitness-reducing traits, such as lethality or sterility, leading to reduction in the numerical size of the pest populations if spread into the target population at sufficiently high frequency. Population modification aims to reduce the harm done by the pest without large changes in the numerical size of the pest population, for example by reducing the ability to transmit disease (“vector competence”) of modified mosquitoes. If such traits, or the DNA sequences encoding them, can be sustained at sufficiently high allele frequency in the target population then the desired harm-reduction outcome should be achieved, by reduction in the number of pests or by reduction in the per-pest harm.
CRISPR/Cas9: a cutting-edge solution for combatting the fall armyworm, Spodoptera frugiperda
28724Gouda, M.N.R., Jeevan, H., Shashank, H.G., Molecular Biology Reports, 51. 2023-12-19 12:15:58.
The utilization of CRISPR/Cas9 in Spodoptera frugiperda, commonly known as fall armyworm, presents a groundbreaking avenue for pest management. With its ability to precisely modify the insect’s genome, CRISPR/Cas9 offers innovative strategies to combat this destructive pest. The application of CRISPR/Cas9 in S. frugiperda holds immense potential. It enables the identification and functional analysis of key genes associated with its behavior, development, and insecticide resistance. This knowledge can unveil novel target sites for more effective and specific insecticides. Additionally, CRISPR/Cas9 can facilitate the development of population control methods by disrupting vital genes essential for survival. However, challenges such as off-target effects and the efficient delivery of CRISPR/Cas9 components remain. Addressing these obstacles is vital to ensure accurate and reliable results. Furthermore, ethical considerations, biosafety protocols, and regulatory frameworks must be integral to the adoption of this technology. Looking forward, CRISPR/Cas9-based gene drive systems hold the potential to promulgate desirable genetic traits within S. frugiperda populations, offering a sustainable and eco-friendly approach. This could curtail their reproductive capabilities or make them more susceptible to certain interventions. In conclusion, CRISPR/Cas9 presents a transformative platform for precise and targeted pest management in S. frugiperda. By deciphering the insect’s genetic makeup and developing innovative strategies, we can mitigate the devastating impact of fall armyworm on agriculture while ensuring environmental sustainability.
Assessing the sterility and quality of gamma-irradiated pepper weevils, Anthonomus eugenii (Coleoptera: Curculionidae), toward the development of the sterile insect technique
28713Basso, J.V., Labbe, R. and Scott-Dupree, C., Pest Management Science, 2023-12-18 09:48:19.
The pepper weevil (PW), Anthonomus eugenii, is an economically significant pest of cultivated Capsicum spp. pepper crops in North America where it remains a challenge to manage because of its cryptic immature life stages. The sterile insect technique (SIT) is a genetic pest management tactic that relies on the release of insects that have been sterilized with ionizing radiation to lower the population reproductive rate. Toward developing an effective PW-SIT program, this study has, for the first time, investigated the effects of gamma irradiation on the sterility and survival of this species. Among the array of doses tested, we found that pupal PW males and females irradiated at 110 Gy produced no adult offspring. Furthermore, females mated with a male irradiated at 110 Gy had high egg sterility (97.3%), and irradiated females nearly completely failed to lay eggs (97.5%). Individuals irradiated at this dose had a shortened lifespan (lethal time to 50% mortality values of 12 and 11 days for males and females, respectively) and quantitatively reduced spontaneous flight activity. The eclosion rate of PW pupae was not significantly reduced by any radiation treatment. This study suggests that PWs irradiated at a gamma radiation dose of 110 Gy as pupae could feasibly be used in a PW-SIT program, because both males and females were 100% sterile at this dose. These findings will inform the development of a SIT program that could considerably improve the sustainability and effectiveness of PW management in greenhouse and field pepper crops worldwide.
Side effects of X-ray irradiation on flight ability of Cydia pomonella moth
28694Huang, S.-W., Zhang, J.-H., Wei, Z.-H., Yang, X.-M., Wang, X.-Y. and Yang, X.-Q., Pest Management Science, 2023-12-12 14:27:29.
The sterile insect technique (SIT) has proven to be an effective approach in managing the population of major invasive pests Our previous studies showed that irradiation of males at a dosage of 366 Gy X-rays resulted in complete sterility. However, the mating competitiveness of sterilized males is significantly compromised, which can be attributed to a decline in their ability to fly. In this study, we examined the flight patterns of both male and female adults of C. pomonella. The results revealed significant variations in the average flight speed of both genders at different stages of maturity, with females displaying longer flight duration and covering greater distances. Effect of irradiation on the flight performance of 3-day-old male moths was further evaluated, as they demonstrated the longest flight distance. The findings indicated a significant decrease in flight distance, duration, and average speed, due to wing deformities caused by irradiation, which also limited the dispersal distance of moths in orchards, as indicated by the mark-and-recapture assay. Quantitative reverse-transcription PCR analysis revealed a down-regulation of flight-related genes such as flightin, myosin heavy chain, and distal-less following radiation exposure. These findings demonstrate that X-ray irradiation at a radiation dose of 366 Gy has a detrimental effect on the flight ability of male C. pomonella adults. These insights not only contribute to a better understanding of how radiation sterilization diminishes the mating competitiveness of male moths, but also aid in the development and improvement of SIT practices for the effectively controlling C. pomonella.
The Sterile Insect Technique can efficiently reduce the reproduction of the spotted wing drosophila (Drosophila suzukii) in strawberry
28688B. Gard, A. Panel, A. Labbetoul, N. Bosshard, A. Xuereb, B. Cariou, A. Debelle, C. Oliva, S. Fellous, bioRxiv, 2023-12-11 13:19:11.
The spotted wing drosophila (SWD) Drosophila suzukii (Diptera: Drosophilidae) is a highly problematic pest in soft fruit crops. Since its introduction in Europe in 2008, no satisfying nor environment-friendly control method has emerged against this species. The sterile insect technique (SIT) has proven efficient at controlling numerous fruit fly species. In recent years, key elements of SIT against D. suzukii have become available, leading to the publication of encouraging results. However, field- and field-like experiments are notoriously under the influence of various, often unidentified factors granting the need for replicated studies. In this experiment, we assayed the efficacy of a high-performance strain at reducing the reproduction of D. suzukii in complex, yet replicated and controlled conditions. Two ratios of sterile to fertile insects (5:1 and 1:1) using bisexual releases were compared to a control treatment with fertile, wild flies only. The presence of sterile individuals at a 5:1 ratio significantly reduced fly reproduction, measured after 5 days, by an approximate threefold factor. However, the proportion of infested fruits in the treated plots remained unaffected. The number of available berries in the cage appeared as an unexpected determinant of fly infestation, suggesting undocumented density-dependent processes. The success of this assay opens the door to larger scales experiments, over several generations, and, in the near future, the field-evaluation of the efficacy of the SIT to control D. suzukii.
Population suppression with dominant female-lethal alleles is boosted by homing gene drive
28685Jinyu Zhu, Jingheng Chen, Yiran Liu, Xuejiao Xu, Jackson Champer, bioRxiv, 2023-12-07 10:24:25.
Methods to suppress pest insect populations using genetic constructs and repeated releases of male homozygotes have recently been shown to be an attractive alternative to older sterile insect technique based on radiation. Female-specific lethal alleles have substantially increased power, but still require large, sustained transgenic insect releases. Gene drive alleles bias their own inheritance to spread throughout populations, potentially allowing population suppression with a single, small-size release. However, suppression drives often suffer from efficiency issues, and the most well-studied type, homing drives, tend to spread without limit. In this study, we show that coupling female-specific lethal alleles with homing gene drive allowed substantial improvement in efficiency while still retaining the self-limiting nature (and thus confinement) of a lethal allele strategy. Using a mosquito model, we show the required releases sizes for population elimination in a variety of scenarios, including different density growth curves, with comparisons to other systems. Resistance alleles reduced the power of this method, but these could be overcome by targeting an essential gene with the drive while also providing rescue. A proof-of-principle demonstration of this system in Drosophila melanogaster was effective in both basing its inheritance and achieving high lethality among females that inherit the construct in the absence of antibiotic. Overall, our study shows that substantial improvements can be achieved in female-specific lethal systems for population suppression by combining them with a gene drive.
New Techniques of Genetic Modification in Pest Control Spark Debate in Canada
28501Sandeep Kunchikor, Express Healthcare Management, 2023-11-26 09:51:07.
Scientists in Canada are urging serious discussions on the use of genetic modification as a new technique in pest control. In a recent report by the Pest Management Regulatory Agency, a branch of Health Canada that regulates pesticide use, experts argue that genetic modification could become a powerful tool as older insecticides lose their effectiveness and climate change leads to new infestations. Already, such techniques are being tested to prevent mosquitoes from spreading malaria. However, the authors of the report caution that there are many unknown variables. They claim that the consequences of releasing synthetic versions of natural organisms could be harmful and permanent.
Framing Challenges and Opportunities for Canada: Expert Panel on Regulating Gene-Edited Organisms for Pest Control
28486CCA (Council of Canadian Academies), Framing Challenges and Opportunities for Canada, 2023-11-21 11:21:00.
Gene-editing technologies are changing approaches to pest management. Rapidly evolving but unproven gene-editing tools could potentially mitigate the impacts of pests in public health, conservation, and agricultural contexts. The use of these tools, however, is accompanied by uncertainties about possible impacts on species and ecosystems, along with broader socioeconomic and cultural risks. Increased globalization and climate change are intensifying pest problems. These factors, combined with the waning effectiveness of many common pest-control tools, will contribute to growing pressure from both native and invasive pests if left unchecked. Opportunities to manage pests with greater effectiveness, lower costs, and increased safety therefore require consideration.
A framework for identifying fertility gene targets for mammalian pest control
25416C. C. Anna, A. Alana, E. Rey, E. Kevin, K. Sebastian, D. Ludovic, C. Jackson, E. C. Samuel, W. M. Philipp and J. G. Neil, bioRxiv, 2023.05.30.542751. 2023-06-01 07:38:46.
Fertility-targeted gene drives have been proposed as an ethical genetic approach for managing wild populations of vertebrate pests for public health and conservation benefit. This manuscript introduces a framework to identify and evaluate target gene suitability based on biological gene function, gene expression, and results from mouse knockout models. This framework identified 16 genes essential for male fertility and 12 genes important for female fertility that may be feasible targets for mammalian gene drives and other non-drive genetic pest control technology. Further, a comparative genomics analysis demonstrates the conservation of the identified genes across several globally significant invasive mammals. In addition to providing important considerations for identifying candidate genes, our framework and the genes identified in this study may have utility in developing additional pest control tools such as wildlife contraceptives.Competing Interest StatementThe authors have declared no competing interest.
The Role of Symbiont-Targeted Strategies in the Management of Pentatomidae and Tephritidae Pests under an Integrated Vision
24996E. Gonella and A. Alma, Agronomy, 13. 2023-04-21 15:11:32.
The interaction between insects and gut bacterial symbionts is, nowadays, regarded as an important element in the implementation of pest management, in consideration of the urgent need for sustainable alternatives to insecticide use. In this framework, a major tool is symbiotic control, with the main ready-to-use application represented by the interruption of obligate symbioses. Two insect families, namely Pentatomidae in the Hemiptera order and Tephritidae in Diptera, have been indicated as outstanding targets for symbiont-oriented control tactics. An important advantage of interrupting obligate symbioses is the target shift from insect to bacteria, which avoids insecticide use; however, the compatibility between this approach and other pest/disease management strategies is crucial to design low-impact pest control programs. Here we present the state of knowledge regarding the integration of symbiont manipulation in sustainable plant protection plans. Research assessing the potential for multitarget applications is reported, as well as studies on the impact of symbiont interruption on nontarget species. Besides symbiont-targeted pest control, another relevant outcome of symbiont manipulation is the restoration of microbial perturbation in mass-reared insects used in pest control programs, which is a required step to allow the success of other tactics, such as the Sterile Insect Technique. Despite the potential contribution that symbiont-targeted strategies may offer to integrated pest management, we point out that operational caveats may emerge in symbiont-oriented control in relation to the target extension on the label directions and to the number of required treatments. Future work is needed to increase the target range and the number of tested formulations exploiting the interruption of bacterial symbioses. This will also require assessment of the effect of different products on beneficial organisms, including biological control agents. Finally, the authorization of formulates for symbiotic control should be taken into consideration by the regulatory bodies, to really promote new readily available control options. © 2023 by the authors.
Bayesian network-based risk assessment of synthetic biology: Simulating CRISPR-Cas9 gene drive dynamics in invasive rodent management
22516E. A. Brown, S. R. Eikenbary and W. G. Landis, Risk Analysis, 2022-05-14 07:22:34.
Gene drive technology has been proposed to control invasive rodent populations as an alternative to rodenticides. However, this approach has not undergone risk assessment that meets criteria established by Gene Drives on the Horizon, a 2016 report by the National Academies of Sciences, Engineering, and Medicine. To conduct a risk assessment of gene drives, we employed the Bayesian network-relative risk model to calculate the risk of mouse eradication on Southeast Farallon Island using a CRISPR-Cas9 homing gene drive construct. We modified and implemented the R-based model "MGDrivE" to simulate and compare 60 management strategies for gene drive rodent management. These scenarios spanned four gene drive mouse release schemes, three gene drive homing rates, three levels of supplemental rodenticide dose, and two timings of rodenticide application relative to gene drive release. Simulation results showed that applying a supplemental rodenticide simultaneously with gene drive mouse deployment resulted in faster eradication of the island mouse population. Gene drive homing rate had the highest influence on the overall probability of successful eradication, as increased gene drive accuracy reduces the likelihood of mice developing resistance to the CRISPR-Cas9 homing mechanism.
Aquatic invasive species specialists’ perceptions on the importance of genetic tools and concepts to inform management
22482T. A. Bernos, K. M. Jeffries and N. E. Mandrak, Biological Invasions, 24:1863-1879. 2022-05-14 07:09:36.
Perceptions related to the importance of genetic research influence the mobilization of genetic tools and concepts to inform conservation actions. Research characteristics, stakeholders’ perspectives, knowledge, and social linkages with geneticists influence the outcome of genetic information for management practices. We surveyed a broad range of aquatic invasive species (AIS) specialists whose opinions, perspectives, and decisions influence AIS decision-making. We assessed perceptions related to the importance of genetic tools and concepts, as well as the appropriateness of genetic biocontrol, and tested whether their expertise, background, and experience influenced perceptions in a predictable way. While perceptions towards genetic tools and concepts were generally heterogeneous, there was a high consensus (84%) related to the importance of eDNA. Most predictors were weakly correlated with importance ratings. Specialists’ genetic knowledge was the strongest predictor of higher importance ratings: the odds of AIS specialists giving higher ratings increased by up to 1.5-fold with increasing genetic knowledge. When evaluating the appropriateness of genetic biocontrol, level of support was lower for approaches based on gene editing (58%) than those relying on traditional hatchery techniques (70%). Support for gene editing varied by geographic location and with specialists’ knowledge of genetics and AIS management. These findings suggest that perceptions towards genetic research vary between genetic tools and concepts and are shaped by the interplay of individual’s values, expertise, experience, and background. To collaborate more effectively, genetic scientists must understand the extent of genetic knowledge of their AIS management partners and recognize that their conceptions of the conservation genetics research-practice space may vary.
Area-wide management of fruit flies in a tropical mango growing area integrating the sterile insect technique and biological control: From a research to an operational programme
19391Liedo, P., Montoya, P. , and Toledo, J., AREA-WIDE INTEGRATED PEST MANAGEMENT: Development and Field Application, 2021-11-29 17:29:33.
The Sterile Insect Technique (SIT) has been successfully used for the control of fruit flies in a number of places in the world. One requirement for its successful application is that wild populations should be at low densities to achieve effective sterile to wild fly overflooding ratios. This has been an important reason that has limited its integration in fruit fly management in tropical fruit growing areas, where climate conditions and the availability of hosts all year-round results in high population densities. Here we report the results of a project where SIT integration into fruit fly management was evaluated under the tropical conditions of the mango growing area in the Soconusco region of Chiapas, Mexico. The basis for the area-wide integrated pest management (AW-IPM) approach was the knowledge of the population dynamics of the pest fruit flies in the region and of the fruit phenology. The main commercial mango growing areas are in the lowlands, where fruit fly populations are very low outside of the mango production season. Population densities are higher in the midlands and highlands, where alternate hosts are common in backyards and as part of the natural vegetation. We call these refuge areas, and the AW-IPM approach aimed at establishing a biological barrier with releases of parasitoids and sterile male fruit flies to suppress the fruit fly populations and prevent or minimize the dispersal of wild flies from the refuge areas to the mango orchards. In 2014, after two years of releases, fruit fly population densities were suppressed more than 70% in the release area and 65% in the entire area, including the lowlands with the mango orchards. With the support of fruit growers, state and federal governments, this project was continued and established as an operational AW-IPM programme. In 2016, after 4 years of programme implementation, the detection of wild flies was significantly reduced, and the number of batches of fruit that were rejected at the packing houses due to the detection of infested fruits was the lowest in the past 12 years, since the recording of these data was initiated. These indicators declined even further in 2017. The results obtained demonstrate that AW-IPM integrating the SIT can be applied successfully against fruit flies under tropical conditions with naturally high pest densities, providing there is adequate knowledge on the population dynamics of the fruit fly species present in the region.
Sterile Insect Technique Programme against Mediterranean Fruit Fly in the Valencian Community (Spain)
16965I. Plá, J. García de Oteyza, C. Tur, M. Á. Martínez, M. C. Laurín, E. Alonso, M. Martínez, Á. Martín, R. Sanchis, M. C. Navarro, M. T. Navarro, R. Argilés, M. Briasco, Ó. Dembilio and V. Dalmau, Insects, 12. 2021-05-04 15:09:26.
The Mediterranean fruit fly, Ceratitis capitata (Wied.), is an endemic pest in fruit-growing areas of the Spanish Mediterranean coast. In the Valencian Community, it represents a serious problem in the cultivation of citrus and numerous species of fruit, such as peach, cherry, apricot, persimmon, etc. For over 50 years, the Department of Agriculture of Valencia has led, promoted, and carried out a C. capitata control programme to protect crops, especially citrus fruits, because this community is the largest national producer and the leading region for fresh citrus exports in the world. Traditionally, pest control has been based on the use of insecticides. However, a reduction of more than 90% of a target wild population was achieved in the frame of a pilot integrated pest management (IPM) project based on the sterile insect technique (SIT), which was implemented from 2003 to 2006. Based on this successful result, in 2007 the Department of Agriculture of Valencia initiated an area-wide integrated pest management (AW-IPM) programme for the suppression of C. capitata, using the SIT as the primary control method. Complementary activities are implemented periodically in hotspots and during different time periods depending on the pest population dynamics. As a result, there has been a reduction of more than 90% in the use of insecticides by aerial means to control C. capitata, as well as a growth trend in exports of citrus and fresh fruits from the Valencian Community in recent years. This paper provides a historical review of the Valencian programme and briefly describes how technological innovations and decision-making tools have contributed to programme efficiency.
Engineered expression of the invertebrate-specific scorpion toxin AaHIT reduces adult longevity and female fecundity in the diamondback moth Plutella xylostella
16653T. Harvey-Samuel, X. Xu, E. Lovett, T. Dafa'alla, A. Walker, V. C. Norman, R. Carter, J. Teal, L. Akilan, P. T. Leftwich, C. M. Reitmayer, H. A. Siddiqui and L. Alphey, Pest Management Science, 2021-03-04 17:21:00.
To increase the flexibility of future genetic pest management systems in the diamondback moth, we aimed to assess the use of a non-cell-autonomous, invertebrate-specific, neurotoxic effector ? the scorpion toxin AaHIT. This AaHIT effector was designed to be secreted by expressing cells, potentially leading to effects on distant cells, specifically neuromuscular junctions. We demonstrated the feasibility of using non-cell-autonomous effectors within a GPM context for the first time in Lepidoptera, one of the most economically damaging orders of insects. These findings provide a framework for extending this system to other pest Lepidoptera and to other secreted effectors.
Projects to target a range of pest control solutions
16366K. McCormack, The Chronicle, 2021-02-10 20:19:28.
With the annual national cost of established vertebrate pest animals estimated to be around $800 million, and over $4 billion for weeds, it’s in Australia’s best interest to try and tackle these pesky problems at their root causes. 19 projects will be funded following a competitive grant process to research and advance breakthrough solutions to control some of Australia’s worst established pest animals and weeds, including fall armyworm and prickly acacia. Minister for Agriculture, Drought and Emergency Management, David Littleproud, said he was delighted with the high calibre and diversity of projects coming from the popular grant round.
RNAi-based products: A sustainable alternative to hazardous pesticides
16211Ghent University, Phys Org, 2021-01-27 13:59:48.
RNAi-based biocontrol is a great alternative to hazardous pesticides and can contribute towards reversing the alarming decline in farmland birds and beneficial insects (especially pollinating ones). RNAi is a well-known natural biological process in most
Drivers of mosquito mating
16110N. C. Manoukis, Science, 371:340. 2021-01-22 15:54:49.
Gene drive systems are based on the release of organisms whose genomes have been modified or engineered to spread a desired allele or trait (such as resistance to the parasites that cause malaria) through a population. Success will depend on the release of genetically modified males that will be able to mate with wild females. Beyond gene drive strategies, in mosquitoes it is understood that only males can be released as part of any genetic pest control (GPC) program (7); females feed on blood to lay eggs, and releasing insects that will feed on humans is widely unacceptable.
Genetic pest management and the background genetics of release strains
15695P. T. Leftwich, L. G. Spurgin, T. Harvey-Samuel, C. J. E. Thomas, L. C. Paladino, M. P. Edgington and L. Alphey, Philosophical Transactions of the Royal Society B: Biological Sciences, 376:20190805. 2020-12-28 15:35:20.
We discuss issues around strain selection and the potential consequences of such introgression. We conclude that such introgression is probably harmless in almost all circumstances, and could, in theory, provide specific additional benefits to the release programme. We outline population monitoring approaches that could be used, going forward, to determine how background genetics may affect GPM. This article is part of the theme issue ‘Novel control strategies for mosquito-borne diseases’.
Further guidance required for assessment of gene drive technology, says EFSA
15137Euractiv, The World News Monitor, 2020-11-16 16:25:26.
Existing guidelines are adequate for evaluating risks associated with gene-drive modified insects, but further guidance is needed for some areas, most notably for environmental risk assessments. The evaluation was requested to explore the issue ahead of the consideration of any possible applications of the technology and is also designed to support the EU in discussions on the biosafety of GMOs in international fora such as the United Nations. It found that while existing guidelines are sufficient for evaluating risks associated with technology, further guidance is needed for some areas, such as molecular characterisation, environmental risk assessment and post-market environmental monitoring.
Adequacy and sufficiency evaluation of existing EFSA guidelines for the molecular characterisation, environmental risk assessment and post-market environmental monitoring of genetically modified insects containing engineered gene drives
15043E. Panel o. G. M. Organisms, H. Naegeli, J.-L. Bresson, T. Dalmay, I. C. Dewhurst, M. M. Epstein, P. Guerche, J. Hejatko, F. J. Moreno, E. Mullins, F. Nogué, N. Rostoks, J. J. Sánchez Serrano, G. Savoini, E. Veromann, F. Veronesi, M. B. Bonsall, J. Mumfor, EFSA Journal, 18:e06297. 2020-11-12 19:24:46.
As a proactive measure, the European Food Safety Authority (EFSA) has been requested by the European Commission to review whether its previously published guidelines for the risk assessment of genetically modified animals (EFSA, 2012 and 2013), including insects (GMIs), are adequate and sufficient for GDMIs, primarily disease vectors, agricultural pests and invasive species, for deliberate release into the environment. Under this mandate, EFSA was not requested to develop risk assessment guidelines for GDMIs. In this Scientific Opinion, the Panel on Genetically Modified Organisms (GMO) concludes that EFSA's guidelines are adequate, but insufficient for the molecular characterisation (MC), environmental risk assessment (ERA) and post-market environmental monitoring (PMEM) of GDMIs. While the MC,ERA and PMEM of GDMIs can build on the existing risk assessment framework for GMIs that do not contain engineered gene drives, there are specific areas where further guidance is needed for GDMIs.
EFSA advises on risk assessment of engineered gene drives
15069EFSA, European Food and Safety Authority, 2020-11-12 18:15:34.
EFSA’s existing guidelines for the risk assessment of genetically modified animals are adequate for evaluating risks associated with gene drive modified insects. However, further guidance is needed for some areas, such as molecular characterisation, environmental risk assessment and post-market environmental monitoring, say EFSA’s experts on Genetically Modified Organisms.
Expert advises farmers to adopt gene drive-based pest control technology
15029S. Thompson, naija247news, 2020-11-09 15:36:25.
Dr Rose Gidado, County Coordinator, Open Forum on Agricultural Biotechnology(OFAB), has advised farmers to adopt the gene drive-based pest control technology. Gidado, also Deputy Director, National Biotechnology Development Agency (NABDA), said the adoption would significantly help to restore Nigeria’s food crop industry. According to her, Nigerian agricultural system is dominated by the application of synthetic pesticides which have resulted in environmental pollution. Gidado said that it had contributed greatly to climate change, with lethal consequences like increased pest attack, decreased crop yield and extreme heat stress in plants. The scientist said the application of gene drive in Nigeria’s agricultural system, would help greatly in the control of deadly insect pests which cause damages to crops and reduction in food production.
The Sterile Insect Technique: Success and Perspectives in the Neotropics
15185D. Perez-Staples, F. Diaz-Fleischer and P. Montoya, Neotropical Entomology, 14. 2020-10-28 15:12:56.
Here, we review SIT in the Neotropics and focus on particular recent successful cases of eradication of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), as well as effective programs used against the Mexican fruit fly Anastrepha ludens (Loew), the New World screwworm fly Cochliomyia hominivorax (Coquerel)), and the Cactus moth Cactoblastis cactorum (Berg). We examine when SIT does not work and innovations that have made SIT more efficient and also highlight complimentary techniques that can be used in conjunction. We address potential candidate species that could be controlled through SIT, for example Philornis downsi Dodge & Aitken. Finally, we consider the impact of climate change in the context of the use of the SIT against these pests. Given the recent dramatic decline in insect biodiversity, investing in environmentally friendly means of pest control should be a priority. We conclude that SIT should be promoted in the region, and leadership and political will is needed for continued success of SIT in the Neotropics.
On Nonlinear Pest/Vector Control via the Sterile Insect Technique: Impact of Residual Fertility
14291M. S. Aronna and Y. Dumont, Bulletin of Mathematical Biology, 82:29. 2020-07-09 14:09:49.
We consider a minimalist model for the Sterile Insect Technique (SIT), assuming that residual fertility can occur in the sterile male population.
Can CRISPR gene drive work in pest and beneficial haplodiploid species?
12389J. Li, O. Aidlin Harari, A.-L. Doss, L. L. Walling, P. W. Atkinson, S. Morin and B. E. Tabashnik, Evolutionary Applications, 2020-06-03 18:14:33.
Gene drives based on CRISPR/Cas9 have the potential to reduce the enormous harm inflicted by crop pests and insect vectors of human disease, as well as to bolster valued species. In contrast with extensive empirical and theoretical studies in diploid organisms, little is known about CRISPR gene drive in haplodiploids, despite their immense global impacts as pollinators, pests, natural enemies of pests, and invasive species in native habitats. Here we analyze mathematical models demonstrating that, in principle, CRISPR homing gene drive can work in haplodiploids, as well as at sex-linked loci in diploids. However, relative to diploids, conditions favoring the spread of alleles deleterious to haplodiploid pests by CRISPR gene drive are narrower, the spread is slower, and resistance to the drive evolves faster. By contrast, the spread of alleles that impose little fitness cost or boost fitness was not greatly hindered in haplodiploids relative to diploids. Therefore, altering traits to minimize damage caused by harmful haplodiploids, such as interfering with transmission of plant pathogens, may be more likely to succeed than control efforts based on introducing traits that reduce pest fitness. Enhancing fitness of beneficial haplodiploids with CRISPR gene drive is also promising.
Mosquito-Borne Diseases Emergence/Resurgence and How to Effectively Control It Biologically
12383H. Dahmana and O. Mediannikov, Pathogens, 9:26. 2020-04-23 17:49:22.
Deadly pathogens and parasites are transmitted by vectors and the mosquito is considered the most threatening vector in public health, transmitting these pathogens to humans and animals. We are currently witnessing the emergence/resurgence in new regions/populations of the most important mosquito-borne diseases, such as arboviruses and malaria. This resurgence may be the consequence of numerous complex parameters, but the major cause remains the mismanagement of insecticide use and the emergence of resistance. Biological control programmes have rendered promising results but several highly effective techniques, such as genetic manipulation, remain insufficiently considered as a control mechanism. Currently, new strategies based on attractive toxic sugar baits and new agents, such as Wolbachia and Asaia, are being intensively studied for potential use as alternatives to chemicals. Research into new insecticides, Insect Growth Regulators, and repellent compounds is pressing, and the improvement of biological strategies may provide key solutions to prevent outbreaks, decrease the danger to at-risk populations, and mitigate resistance.
Simulating effects of fitness and dispersal on the use of Trojan sex chromosomes for the management of invasive species
11488C. C. Day, E. L. Landguth, R. K. Simmons, W. P. Baker, A. R. Whiteley, P. M. Lukacs and A. Bearlin, Journal of Applied Ecology, 2020-03-19 20:15:27.
The use of Trojan Y chromosomes (TYC) for controlling invasive species involves manipulating the sex chromosomes of captive-raised individuals. Following release, the offspring of these individuals consist of only one sex, thereby skewing the sex ratio of the invasive population and potentially leading to eradication. Simulation models are needed that can inform managers about how to maximize the likelihood of invasive species eradication, since implementation of this novel management approach in the field is still rare. Here, we present the first spatially explicit, mechanistic simulation model of a real-world TYC program for invasive species eradication. Using a brook trout Salvelinus fontinalis system model, we investigated the effects of competitive and reproductive fitness of the captive-raised YY males, dispersal behaviour upon their release and landscape heterogeneity on eradication success. Likelihood of eradication was dependent on both the competitive and reproductive fitness of the Trojan individuals. Competitive fitness (i.e. survival) had a higher threshold for eradication, below which the invasive populations were not eradicated. Movement ecology of both the wild and YY male populations was important for eradication. Under a restricted dispersal scenario for YY males following their release, the wild population was not extirpated but maintained a stable, yet reduced, population size. Analysis of landscape configuration indicated that time to eradication of local patches increased with greater connectivity within the stream network. In addition to sex ratio distortion, density-dependent mortality resulting from outplantings made an important contribution to population decline and therefore may also affect native competitors. Synthesis and applications. The use of Trojan sex chromosomes to skew population sex ratios is a novel method for the suppression and eradication of aquatic invasive species. Results from our modelling work indicate that while eradication is possible, maximizing its likelihood requires an understanding of the fitness and movement ecology of both the wild and YY male populations of the invasive species. Both our model and the principles derived from this study related to fitness and behavioural landscape ecology can be broadly applied to other invaded species and systems.
Understanding the Science of Gene Drive and the Potential for an Improved Crop Pest Control System in Nigeria
14882A. Isah and R. S. M. Gidado, OFAB Nigeria, 2020-02-26 15:52:39.
Several studies have shown that the Cas9-mediated gene drive technology is cheaper and will be easily affordable by the efficient Nigerian scientists to explore. The application of the gene drive technologies have many more controls over several other devastating insects in Nigeria and may be very necessary to adopt it to rescue our ailing food crop industry from the attack by destructive insect pest of crops.
Metaphor, Trust and Support for Non-native Species Control
13833P. A. Kohl, S. J. Collins and M. Eichholz, Environmental Communication, 14:672-685. 2020-01-07 15:29:47.
This experimental study used a representative sample of U.S. residents (N = 1,042) to test whether the use of the term "invasive" increases support for non-native species control efforts. The term invasive had a small influence on support for two out of three non-native species control methods. We also found stronger support for control methods using gene editing technologies than control methods using poison.
Genetic pest management technologies to control invasive rodents
11576D. Kanavy and D. Threadgill, Island invasives: scaling up to meet the challenge, 2019-03-05 15:20:05.
Many strategies exist to manage invasive pests on islands, ranging from poison to trapping, with varying degrees of success. Genetic technologies are increasingly being applied to insect pests, but so far, not to vertebrates. We are implementing a genetic strategy to eradicate invasive mouse populations as another tool for pest control. Mus musculus, the common house mouse, is one of the most widespread invasive species. Mice threaten human health, agriculture, and biodiversity on many islands, particularly seabirds. Seabirds are endangered indirectly through competition for resources or predators being attracted by the mice or directly with mice attacking chicks and eggs. Rodenticides are the most common method of eradicating mice, but their use leads to poisoning of non-target species and has limited efficacy against mice. An approach that could eliminate non-target species impact would be to engineer daughterless mice linked to a gene drive system for self-sustained propagation. For this project, we have investigated exploiting a naturally occurring gene drive, the t-complex. Using the t w2 haplotype of the t-complex, we observed the t w2 haplotype being transmitted to offspring with a transmission distortion ratio of 95.3%. The daughterless phenotype is being accomplished by inserting the Sry gene (male sex-determining gene) into an autosome containing the tw2 haplotype via CRISPR/Cas9 gene editing. The presence of Sry will induce testis formation, regardless of the sex chromosomes naturally inherited. When Sry is inserted into the t-complex, the desired gene will spread through the population, eliminating female offspring. This model system will support studies to evaluate the effectiveness of crashing an invasive population without adversely affecting other
Trialling gene drives to control invasive species: what, where and how?
11573T. Harvey-Samuel, K. J. Campbell, M. Edgington and L. Alphey, Island invasives: scaling up to meet the challenge, 2019-03-05 15:16:48.
The control of invasive species would be enhanced through the addition of novel, more effective and sustainable pest management methods. One control option yet to be trialled in the field is to deploy transgene-based ‘Gene Drives’: technologies which force the inheritance of a genetic construct through the gene pool of a wild population, suppressing it or replacing it with a less harmful form. There is considerable interest in applying gene drives to currently intractable invasives across a broad taxonomic range. However, not all species will make efficient or safe targets for these technologies. Additionally, the safety and efficacy of these systems will vary according to where they are deployed, the specific molecular design chosen, and how these factors interact with the ecology of the target pest. Given the transformative but also controversial nature of gene drives, it is imperative that their first field trials are able to successfully demonstrate that they can be used safely and efficiently. Here, we discuss how to maximise the probability of this outcome through considering three important questions: What types of invasive species should we use to trial gene drives? Where should we be trialling them? and How should these trials be conducted? In particular, we focus on the ecological, genetic and geographic features of small, isolated islands which make them ideal locations for these initial trials. A case study of an island invasive that is deemed highly appropriate for gene drive intervention, and for which gene drive development is currently underway (Mus musculus), is used to further explore these concepts
Towards a genetic approach to invasive rodent eradications: assessing reproductive competitiveness between wild and laboratory mice
11570M. Serr, N. Heard and J. Godwin, Island invasives: scaling up to meet the challenge, 2019-03-05 15:10:12.
House mice are significant invasive pests, particularly on islands without native mammalian predators. As part of a multi-institutional project aimed at suppressing invasive mouse populations on islands, we aim to create heavily male-biased sex ratios with the goal of causing the populations to crash. Effective implementation of this approach will depend on engineered F1 wild-lab males being effective secondary invaders that can mate successfully. As a first step in assessing this possibility, we are characterising genetic and behavioural differences between Mus musculus strains in terms of mating and fecundity using wild house mice derived from an invasive population on the Farallon Islands (MmF), a laboratory strain C57BL/6/129 (tw2), and F1 wild-lab off spring. Mice with the ‘t allele’ (tw2) have a naturally occurring gene drive system. To assess fertility in F1 wild-lab crosses, tw2 males were paired with wild-derived females from the Farallon Islands (MmF). Results of these matings indicate litter sizes are comparable but that weaned pup and adult wild-lab mice are heavier in mass. Next, we initiated tests of male competitiveness using larger (3 m2 ) enclosures with enrichment. We introduced both an MmF and a tw2-bearing male to two MmF females to assess mating outcomes. Preliminary results of these experiments show none of the offspring carried the t-allele. However, performing the same experiment with F1 wildlab males instead of a full lab background resulted in 70% of off spring carrying the t w2 allele. This indicates that F1 wildlab males may be able to successfully compete and secondarily invade. It will be important in subsequent experiments to determine what characteristics contribute to secondary invasion success. More generally, a better understanding of characteristics contributing to overall success in increasingly complex and naturalistic environments will be critical in determining the potential of a gene drive-based eradication approach for invasive mice on islands
A potential new tool for the toolbox: assessing gene drives for eradicating invasive rodent populations
11550K. J. Campbell, J. R. Saah, P. R. Brown, J. Godwin, F. Gould, G. R. Howald, A. Piaggio, P. Thomas, D. M. Tompkins, D. Threadgill, J. Delborne, D. Kanavy, T. Kuiken, H. Packard, M. Serr and A. Shiels, Island invasives: scaling up to meet the challenge, 2019-03-05 14:59:34.
Invasive rodents have significant negative impacts on island biodiversity. All but the smallest of rodent eradications currently rely on island-wide rodenticide applications. Although signifi cant advances have been made in mitigating unintended impacts, rodent eradication on inhabited islands remains extremely challenging. Current tools restrict eradication eff orts to fewer than 15% of islands with critically endangered or endangered species threatened by invasive rodents. The Genetic Biocontrol of Invasive Rodents partnership is an interdisciplinary collaboration to develop and evaluate gene drive technology for eradicating invasive rodent populations on islands. Technological approaches currently being investigated include the production of multiple strains of Mus musculus with a modifi ed form of the native t-complex, or a CRISPR gene drive, carrying genes or mechanisms that determine sex. These systems have the potential to skew the sex ratio of off spring to approach 100% single-sex, which could result in population collapse. One goal proposed is to test the ability of constructs to spread and increase in frequency in M. musculus populations in biosecure, captive settings and undertake modelling to inform development and potential deployment of these systems. Structured ecologically-based risk assessments are proposed, along with social and cultural engagement to assess the acceptability of releasing a gene drive system. Work will be guided by an external ethics advisory board. Partners are from three countries with significant regulatory capacity (USA, Australia, New Zealand). Thus, we will seek data sharing agreements so that results from experiments may be used within all three countries and treat regulatory requirements as a minimum. Species-specific, scalable, and socially acceptable new eradication tools could produce substantial biodiversity benefits not possible with current technologies. Gene drive innovation may provide such a tool for invasive species management and be potentially transformative and worthy of exploring in an inclusive, responsible, and ethical manner.
Controlling invasive rodents via synthetic gene drive and the role of polyandry
3927Manser, AC, S. J.; Sutter, A.; Blondel, D. V.; Serr, M.; Godwin, J.; Price, T. A. R., Proceedings of the Royal Society B-Biological Sciences, 286:9. 2019-01-05 00:00:00.
House mice are a major ecosystem pest, particularly threatening island ecosystems as a non-native invasive species. Rapid advances in synthetic biology offer new avenues to control pest species for biodiversity conservation. Recently, a synthetic sperm-killing gene drive construct called t-Sry has been proposed as a means to eradicate target mouse populations owing to a lack of females. A factor that has received little attention in the discussion surrounding such drive applications is polyandry. Previous research has demonstrated that sperm-killing drivers are extremely damaging to a male's sperm competitive ability. Here, we examine the importance of this effect on the t-Sry system using a theoretical model. We find that polyandry substantially hampers the spread of t-Sry such that release efforts have to be increased three-to sixfold for successful eradication. We discuss the implications of our finding for potential pest control programmes, the risk of drive spread beyond the target population, and the emergence of drive resistance. Our work highlights that a solid understanding of the forces that determine drive dynamics in a natural setting is key for successful drive application, and that exploring the natural diversity of gene drives may inform effective gene drive design.
Sustainability as a framework for considering gene drive mice for invasive rodent eradication
3886Barnhill-Dilling, SKS, M.; Blondel, D. V.; Godwin, J., Sustainability, 11:1334. 2019-01-04 00:00:00.
Gene drives represent a dynamic and controversial set of technologies with applications that range from mosquito control to the conservation of biological diversity on islands. Currently, gene drives are being developed in mice that may one day serve as an important tool for reducing invasive rodent pests, a key threat to island biodiversity and economies. Gene drives in mice are still in development in laboratories, and wild release of modified mice is likely a distant reality. However, technological changes outpace the existing capacity of regulatory frameworks, and thus require integrated governance frameworks. We suggest sustainability-which gives equal consideration to the environment, economy, and society-as one framework for addressing complexity and uncertainty in the governance of emerging gene drive technologies for invasive species management. We explore the impacts of rodent gene drives on island environments, including potential conservation and restoration of island biodiversity. We outline considerations for rodent gene drives on island economies, including impacts on agricultural and tourism losses, and reductions in biosecurity costs. Finally, we address the social dimension as an essential space for deliberation that will be integral to evaluating the potential deployment of gene drive rodents on islands.
Yes we can! Exciting progress and prospects for controlling invasives on islands and beyond
7964D. Simberloff, B. Keitt, D. Will, N. Holmes, E. Pickett and P. Genovesi, Western North American Naturalist, 78:942-958. 2018-10-22 14:34:34.
Eradication and maintenance management of island invasive species have long histories, and incremental improvements of existing technologies plus occasional novel approaches have led to more challenging targets and increased success rates in certain categories. Many nonnative mammals have been eradicated from islands, as have several nonnative birds, insects, and plants. Hundreds of rat populations have been eliminated, with a success rate over 80%, and islands over 10,000 ha are now feasible targets. Mouse eradication has proven more challenging, but aerial broadcast of anticoagulant toxins has led to increased success. Carnivore eradication-especially of feral housecats and foxes-has been frequently attempted with a recent success rate over 90%. Eradication of herbivores-primarily goats, rabbits, wild boar, and boar/pig hybrids-has been attempted almost 200 times, with a success rate over 90%. Trends in mammal eradication include more frequent attempts and higher success rates on larger islands and inhabited islands, as well as attempts targeting multiple invasive species. Documented conservation gains from island mammal eradications are numerous. For insects, about two-thirds of some 50 island attempts have succeeded, and most targeted agricultural pests. No summary statistics exist on island plant eradications, but several small infestations have been eradicated. Several insect and plant island invaders have been maintained at low densities by biological control, and plants have been controlled short of eradication by herbicides, often combined with physical or mechanical means. Failures in both eradication and maintenance management on islands often result from insufficient long-term commitment of resources. Excitement and controversy abound over the prospect that new techniques relying on molecular genetic tools-especially RNA-guided gene drives-may permit eradication or maintenance management of nonnative invaders in situations that have previously appeared extremely difficult or infeasible. Island populations of invertebrates, small mammals, and some plants are particularly propitious targets.
Identifying knowledge gaps for gene drive research to control invasive animal species: The next CRISPR step
3998Moro, DB, Margaret; Kennedy, Malcolm; Campbell, Susan; Tizard, Mark, Global Ecology and Conservation, 13:e00363. 2018-01-16 00:00:00.
Invasive animals have been linked to the extinctions of native wildlife, and to significant agricultural financial losses or impacts. Current approaches to control invasive species require ongoing resources and management over large geographic scales, and often result in the short-term suppression of populations. New and innovative approaches are warranted. Recently, the RNA guided gene drive system based on CRISPR/Cas9 is being proposed as a potential gene editing tool that could be used by wildlife managers as a nonlethal addition or alternative to help reduce pest animal populations. While regulatory control and social acceptance are crucial issues that must be addressed, there is an opportunity now to identify the knowledge and research gaps that exist for some important invasive species. Here we systematically determine the knowledge gaps for pest species for which gene drives could potentially be applied. We apply a conceptual ecological risk framework within the gene drive context within an Australian environment to identify key requirements for undertaking work on seven exemplar invasive species in Australia. This framework allows an evaluation of the potential research on an invasive species of interest and within a gene drive and risk context. We consider the currently available biological, genetic and ecological information for the house mouse, European red fox, feral cat, European rabbit, cane toad, black rat and European starling to evaluate knowledge gaps and identify candidate species for future research. We discuss these findings in the context of future thematic areas of research worth pursuing in preparation for a more formal assessment of the use of gene drives as a novel strategy for the control of these and other invasive species.
Trojan Females and Judas Goats: Evolutionary Traps as Tools in Wildlife Management
13743B. A. Robertson, R. S. Ostfeld and F. Keesing, Bioscience, 67:982-993. 2017-11-01 19:42:43.
Here, we bring together science from the pest-control, eco-evolutionary, and conservation communities to outline how evolutionary traps can be repurposed to eliminate or control pest species. We highlight case studies and devise strategies for the selection of appropriate cues to manipulate, traits to target, and mechanisms to use in setting evolutionary traps that will most rapidly reduce animal abundance while preventing evolutionary escape. We find that evolutionary traps are demonstrably effective and unique tools with high target-species specificity that are deployable in concert with more traditional approaches.
The potential for the use of gene drives for pest control in New Zealand: a perspective
14253P. K. Dearden, N. J. Gemmell, O. R. Mercier, P. J. Lester, M. J. Scott, R. D. Newcomb, T. R. Buckley, J. M. E. Jacobs, S. G. Goldson and D. R. Penman, Journal of the Royal Society of New Zealand, 48:225-244. 2017-10-25 14:20:45.
Here we describe the current state of gene drive technologies and present a series of examples to examine the potential benefits and problems arising from gene drive approaches for pest control in New Zealand.
The optimal implementation of the Trojan Y chromosome eradication strategy of invasive species
11510M. R. Kelly and X. Y. Wang, Journal of Biological Systems, 25:399-418. 2017-08-02 15:25:17.
Invasive aquatic species continue to be a persistent problem around the world. The Trojan Y Chromosome (TYC) eradication strategy has recently been developed to help fight the problem in aquatic systems by targeting only the invasive species, sparing native marine stock. It involves rearing genetically modified samples of the invasive species and introducing them into the environment to alter the sex ratio of the invasive population. The paper is devoted to finding the optimal implementation of the TYC eradication strategy of an invasive species as well as a modified, potentially more cost-effective strategy. The modified TYC strategy (MTYC) eliminates one round of exposure to sex hormones compared to the TYC strategy. After introducing both strategies, the optimal control problems for each are formulated. The two strategies are compared through numerical simulations. Our results illustrate that the MTYC strategy, with lower implementation costs, is a better strategy option when trying to minimize the overall effective cost in most scenarios.
Trends in the development of mammalian pest control technology in New Zealand
13735C. T. Eason, L. Shapiro, S. Ogilvie, C. King and M. Clout, New Zealand Journal of Zoology, 44:267-304. 2017-06-19 19:31:49.
The use of new toxins with advantages in specific settings should be complemented by improvements in resetting trap technology, barrier approaches, and novel biocontrol and genetic concepts. Sodium fluoroacetate (1080) and other important tools have been retained; we have the ingredients for transformational change, and new tools are emerging from a research and development pipeline. However, there has been limited practical experience with emerging technologies compared with traditional or 1080 baits.
Towards the genetic control of invasive species
4047Harvey-Samuel, TA, T.; Alphey, L., Biological Invasions, 19:1683-1703. 2017-01-05 00:00:00.
Invasive species remain one of the greatest threats to global biodiversity. Their control would be enhanced through the development of more effective and sustainable pest management strategies. Recently, a novel form of genetic pest management (GPM) has been developed in which the mating behaviour of insect pests is exploited to introduce genetically engineered DNA sequences into wild conspecific populations. These 'transgenes' work in one or more ways to reduce the damage caused by a particular pest, for example reducing its density, or its ability to vector disease. Although currently being developed for use against economically important insect pests, these technologies would be highly appropriate for application against invasive species that threaten biodiversity. Importantly, these technologies have begun to advance in scope beyond insects to vertebrates, which include some of the world's worst invasives. Here we review the current state of this rapidly progressing field and, using an established set of eradication criteria, discuss the characteristics which make GPM technologies suitable for application against invasive pests.
Invertebrate Biosecurity Challenges in High-Productivity Grassland: The New Zealand Example
13738S. L. Goldson, B. I. P. Barratt and K. F. Armstrong, Frontiers in Plant Science, 7. 2016-11-15 19:35:24.
This review explores the unique challenges faced by pasture biosecurity and what may be done to confront existing difficulties. While there is no silver bullet, and limited opportunity pre and at for improving pasture biosecurity, advancement may include increased and informed vigilance by farmers, pheromone traps and resistant plants to slow invasion. Increasingly, there is also the potential for more use of improved population dispersal models and surveillance strategies including unmanned aerial vehicles, as well as emerging techniques to determine invasive pest genomes and their geographical origins.
The Trojan Female Technique for pest control: a candidate mitochondrial mutation confers low male fertility across diverse nuclear backgrounds in Drosophila melanogaster
13733D. K. Dowling, D. M. Tompkins and N. J. Gemmell, Evolutionary Applications, 8:8710880. 2015-07-15 19:28:56.
The Trojan Female Technique (TFT) was recently proposed as a prospective approach to biological pest control. However, applicability of the TFT relies on mitochondrial mutations whose male-sterilizing effects are general across nuclear genomic contexts. We test this assumption, expressing the candidate TFT-mutation bearing haplotype alongside a range of nuclear backgrounds and comparing its fertility in males, relative to that of control haplotypes
Regulatory experience and challenges for the release of GM insects
4135Beech, C, Journal Fur Verbraucherschutz Und Lebensmittelsicherheit-Journal of Consumer Protection and Food Safety, 9:S71-S76. 2014-01-13 00:00:00.
Genetically modified (GM) insects are a potentially valuable new tool for the biological control of insect pests of humans, animals and plants. Considerable progress has been made recently in transfer of GM insects from the laboratory to release and evaluation in the environment. As with other new genetic technologies, regulatory agencies have often found it challenging to determine the regulatory regime under which they should be evaluated, and have either adapted existing regulatory frameworks or adopted new ones. No country has legislation specifically for GM insects. However, irrespective of the regulatory regime under which they are evaluated, the purpose of their regulation remains the same; to protect human health and the environment. Consequently there are evaluation themes common to their regulatory scrutiny, which are elucidated here. There have also been some challenges and issues encountered during the risk evaluation for field release of GM insects, and this paper will highlight some of these to assist others when considering policy, regulation and assessment of GM insects. Useful regulatory and policy precedents also exist from the regulation of biological control agents and the global protection of plants from pests under the International Standards for Phytosanitary Measures (ISPM) framework. Where countries do not have existing regulations, these evaluation instruments could have the potential to be adapted to form a suitable framework for the assessment of risk for GM insects. Finally, some considerations for future policy and regulation in this area are discussed.
Demographic effects on the use of genetic options for the control of mosquitofish, Gambusia holbrooki
11528R. E. Thresher, M. Canning and N. J. Bax, Ecological Applications, 23:801-814. 2013-06-01 15:57:26.
This study tests the sensitivity of genetically based pest control options based on sex ratio distortion to intra-and intersexual aggressive interactions that affect male and female survival and fitness. Data on these interactions and their impacts were gathered for the mosquitofish Gambusia holbrooki (Poeciliidae), a promiscuous species with a strongly male-biased operational sex ratio and well-documented male harassment of females. The experimental design consisted of an orthogonal combination of two population densities and three sex ratios, ranging from strongly male-biased to strongly female-biased, and long-term observations of laboratory populations. Contrary to expectations, the number of males in a population had little evident effect on population demographics. Rather, the density of adult females determined population fecundity (as a result of a stock-recruitment relationship involving females, but not males), constrained male densities (apparently as a result of cannibalism or intersexual aggression), and regulated itself (most likely through effects of intrasexual aggression on female recruitment). The principal effect of males was to constrain their own densities via effects of male-male aggression on adult male mortality rates. Through use of a realistically parameterized genetic/demographic model, we show that of three different genetic options applied to control G. holbrooki, one based on recombinant sex ratio distortion (release of Female Lethal carriers) is marginally more efficient than a sterile male release program, and both outperform an option based on chromosomal sex ratio distortion (Trojan W). Nonlinear dependence of reproductive rate on female density reduces the efficacy of all three approaches. The major effect of intra-and intersexual aggression is mediated through females, whose interactions reduce female numbers and increase the efficacy of a control program based on sex ratio. Socially mediated male mortality has a small impact on control programs due to operational sex ratios that are heavily male-biased. The sensitivity of sex ratio-based control options to social factors will depend on the mating system of the targeted pest, but evidence of widespread density-dependent population regulation suggests that, for most species, the effects of elevated adult mortality (due to intra-and intersexual aggression) on control programs are likely to be slight.
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