Keywords: Biological control
Biocontrol practitioners’ perspectives on emerging genetic-based technologies for weed management
35412Rafter, M.A., Kumaran, N., Brookes, D.R. et al., BioControl, 2026-01-31 16:43:25.
Weed biocontrol researchers have been at the forefront of developing management solutions for invasive weeds for over 100 years and have a unique perspective to offer on the emerging field of genetic-based technologies such as gene drive and RNAi. As part of the XVI International Symposium on Biological Control of Weeds in May 2023 we conducted a focus group discussion workshop to explore biocontrol practitioners’ perspectives related to: (1) Genetic-based control technologies, and the factors influencing support (or not) for their application to weed management, especially weed biocontrol, (2) perceived opportunities to apply genetic-based control tools to enhance or complement weed biocontrol, focusing on whether/how genetic tools can be applied to fundamentally change the practice of weed biocontrol, and (3) genetic-based control in weed management and how it can operate within the Access and Benefit Sharing regulatory landscape. We analyse the perspectives of biocontrol scientists from the workshop and discuss the prospects and challenges of integrating novel genetic-based control tools with weed biocontrol.
Wolbachia as a transformative tool for mosquito-borne disease control: a comprehensive review of mechanisms, efficacy, and future directions
35325Minaei, M. E., Yousefi Nojookambari, N., Ghodraty, M., & Yazdansetad, S., Pathogens and Global Health, 2025-12-23 12:15:44.
Mosquito-borne infectious diseases such as dengue, Zika, chikungunya, and malaria continue to pose significant public health challenges worldwide. Traditional control methods, including the use of insecticides and environmental management, have shown limited effectiveness due to insecticide resistance and logistical challenges. Wolbachia-based strategies, which leverage the bacterium’s unique ability to manipulate mosquito reproduction and block pathogens, present a promising, albeit not universally applicable, method for reducing the transmission of mosquito-borne diseases. Field trials have demonstrated significant but variable efficacy. This systematic review synthesizes the latest findings on Wolbachia-based interventions, focusing on their mechanisms, efficacy, and potential for large-scale implementation. We conducted a comprehensive literature search across multiple databases, including PubMed, Scopus, and Web of Science, to identify relevant studies published between 1990 and 2025. Our review highlights the promising results of Wolbachia-based strategies in reducing mosquito populations and disease transmission, while also addressing the challenges and limitations of this approach. We conclude that Wolbachia-based strategies hold great potential for revolutionizing mosquito-borne disease control, but further research and careful consideration of ecological and ethical implications are necessary for their successful implementation.
Wolbachia-Based biocontrol of Aedes aegypti: Current Progress, Challenges, and future prospects
35217Ashif Ahamed, Safdar Ali, Mehboob Hoque, Journal of Invertebrate Pathology, 2025-10-05 13:03:30.
Wolbachia is used as potential bio-control tool to reduce the dengue mosquitoes and also to reduce dengue virus (DENV) load in transinfected Aedes aegypti. Different field trials including the ones by the World Mosquito Program (WMP) have deployed Wolbachia carrying DENV primary vectors at different target sites worldwide. Field trials suggest that through the Population Replacement Strategy (PRS) and Incompatible Insect Technique (IIT), Wolbachia can introgress into the local Ae. aegypti population or reduce the population size of the Aedes aegypti by cytoplasmic incompatibility phenomenon and subsequent reduction in dengue incidences at target sites. Challenges for this strategy are to establish and maintain the transinfected mosquito population, choosing the appropriate strain of the bacteria, long term establishment of transinfected dengue mosquitoes for several subsequent generations, selecting the appropriate approach of mosquito field release, operational challenges, and the viral evolution. Moreover, the outcome of Wolbachia mediated biological control of Aedes aegypti in a broad scale is yet to be seen and the long-term stability of Wolbachia in transinfected mosquitoes remains unconfirmed. Significant success has been recorded in a broad scale deployment of wAlbB-carrying Aedes aegypti through the ongoing Wolbachia Malaysia project, resulting in a reduction in dengue fever cases. Successful large-deployment of this strategy has also been performed in Colombia and Indonesia (1.7 to 3.3 million people and 135–540 km2 area). Similar investigations on broad scale for longer period across different environmental conditions using transinfected mosquito deployment and associated risk analysis are imperative before adopting this biological control approach as a potent dengue control strategy worldwide.
Long-Term Durability and Public Health Impact of City-Wide wMel Wolbachia Mosquito Releases in Niterói, Brazil, During a Dengue Epidemic Surge
35107Anders, Katherine L., Gabriel Sylvestre Ribeiro, Renato da Silva Lopes, Pilar Amadeu, Thiago Rodrigues da Costa, Thais Irene Souza Riback, Karlos Diogo de Melo Chalegre, Wesley Pimentel de Oliveira, Cátia Cabral da Silva, Marcos Vinicius Ferreira Mendes B, Tropical Medicine and Infectious Disease, 10. 2025-09-02 18:57:03.
In 2024, the Americas experienced the largest dengue outbreak on record and Brazil was among the worst affected countries, reporting 6.6 million cases and 6200 deaths. We report the long-term entomological and epidemiological effectiveness of city-wide deployment of wMel-strain Wolbachia-infected Aedes aegypti in Niterói, a city of half a million people in Rio de Janeiro state, where Wolbachia releases across three-quarters of the urban population in 2017–2019 were expanded to remaining populated areas in 2023. wMel was durably established at ≥95% prevalence in Ae. aegypti populations throughout Niterói four years post-release, and up to seven years in the earliest release sites. Notified dengue case incidence in Niterói was 89% lower following Wolbachia releases, compared to the 10-year pre-intervention period of 2007–2016. Dengue incidence in Niterói in 2024, during a period of record high incidence in Brazil and the region, was 374 per 100,000 population, substantially lower than overall in Rio de Janeiro state (1884 per 100,000) and nationwide in Brazil (3157 per 100,000). Our findings show that city-wide Wolbachia coverage in Niterói provided sustained population-level reduction in dengue incidence throughout the five years post-intervention, including during the 2024 epidemic surge, averting an estimated three-quarters of the dengue case burden that may otherwise have been expected in Niterói in 2024.
‘Toxic Male Technique’ promises faster biocontrol of mosquito populations
34223Macquarie University, Phys.org, 2025-01-07 20:57:52.
A new biological pest control method that targets the lifespan of female insects could significantly reduce the threat of insect pests such as disease-carrying mosquitoes by offering faster and more effective results than current methods. Described in Nature Communications, the technique developed by researchers in Applied BioSciences and the ARC Center of Excellence in Synthetic Biology at Macquarie University is a new approach called the Toxic Male Technique (TMT). It works by genetically engineering male insects to produce insect-specific venom proteins in their semen. When these males mate with females, the proteins are transferred, significantly reducing female lifespan and their ability to spread disease. Insect pests pose a growing threat to global health and agriculture, causing hundreds of thousands of deaths, millions of infections, and costing billions in health care and crop damage annually. In mosquitoes like Aedes aegypti and Anopheles gambiae, only the females bite and transmit diseases such as malaria, dengue, Zika, chikungunya disease and yellow fever. Pesticides face declining effectiveness due to resistance and have caused harm to non-target species and ecosystems. Genetic biocontrol has emerged as a promising alternative. Current techniques like the Sterile Insect Technique (SIT) or insects carrying lethal genes (RIDL) work by releasing massive numbers of sterilized or genetically modified males to mate with the wild females. While these mated females produce no offspring or only male offspring, they continue to blood-feed and spread disease until they die naturally—meaning populations of biting females only decrease when the next generation emerges. By immediately reducing the biting female population, TMT offers significant advantages over competing genetic biocontrol methods. "As we've learned from COVID-19, reducing the spread of these diseases as quickly as possible is important to prevent epidemics," says lead author Sam Beach.
Exploration of the potential of a boosted sterile insect technique to control fruit flies in mango orchards
30856Esther Gnilane Diouf, Thierry Brévault, Saliou Ndiaye, Cyril Piou, Pest Management Science, 2024-06-28 15:39:38.
An innovative version of the sterile insect technique (SIT) for pest control, called boosted SIT, relies on the use of sterile males coated with a biocide to control a target wild pest population of the same species. The objective of the present study was to assess the relevance of such technology to control the fruit fly Bactrocera dorsalis and fruit losses in mango orchards using. An agent-based simulation model named BOOSTIT was used to explore the reduction of fruit losses thank to sterile male fruit flies control and economic benefits according to different strategies of sterile male release. The simulation considered a landscape of 30.25 ha made up of four mango orchards. The SIT and the boosted SIT reduced fruit losses when releases were made before the mango fruiting period. According to model simulations, releases should be performed at least seven times at 2-week intervals and with a sterile/wild male ratio of at least 10:1. Considering the benefit/cost ratio (BCR), few releases should be done with a late start date. The BCR showed economic gains from the two control methods, the number of saved fruits and BCR being higher for SIT. Our simulations showed that SIT would have better results than the boosted SIT to contribute to an effective control of Bactrocera dorsalis at the scale of a small landscape. We highlight the need for laboratory studies of other types of pathogen to find a suitable one with higher incubation time and lower cost. © 2024 Society of Chemical Industry.
The Perpetual Vector Mosquito Threat and Its Eco-Friendly Nemeses
29088Miranda, L.S.; Rudd, S.R.; Mena, O.; Hudspeth, P.E.; Barboza-Corona, J.E.; Park, H.-W.; Bideshi, D.K., Biology, 13:182. 2024-04-04 09:42:02.
Aedes, Culex, and Anopheles mosquitoes are the most prolific arthropod vectors of viral and parasitic agents of debilitating and lethal diseases in humans and animals. Despite some success in integrated pest management programs to control vectors, mosquito-borne diseases, such as dengue and dengue hemorrhagic fever, yellow fever, chikungunya, West Nile, and Zika, and parasitic diseases, such as malaria, lymphatic filariasis, and river blindness, continue to threaten the health and well-being of half the world’s population, many of whom live in economically and medically challenged societies. The perpetual problem inflicted by vector-borne diseases is compounded by the selection for resistance to synthetic pesticides, globalization, and climate change. The latter appears to be the most significant factor implicated in the geographic expansion of mosquitoes. Here, we present a review of these challenges and highlight traditional vector control strategies that employ synthetic pesticides, and “green” eco-friendly technologies that include SIT, IIT, RIDL, CRISPR/Cas9/Cas13 gene drive systems, and biological control, with an emphasis on Lysinibacillus sphaericus and Bacillus thuringiensis subsp. israelensis (Bti).
The organizational structure of global gene drive research
29047Florian Rabitz, Global Environmental Change, 84. 2024-03-19 18:00:17.
Gene drives are a proposed method for large-scale in situ genetic engineering.
Wolbachia still works when it is warm
28809McKay, A., Nature Ecology and Evolution, 8. 2024-01-16 13:59:40.
Wolbachia is a maternally inherited endosymbiotic bacterium that can impede the transmission of viruses such as dengue and Zika by some mosquito vectors to humans. Over the past decade, this self-sustaining disease-control method has been rolled out in cities of increasing size; 2023 saw the largest demonstration of efficacy to date, in Medellín, Colombia. However, two key biological mechanisms that enable Wolbachia-carrying mosquitoes to spread in a population — cytoplasmic incompatibility and maternal transmission — have been shown in laboratory conditions to decline under high temperatures. Writing in Nature Climate Change in August 2023, Vásquez and colleagues conducted computational simulations to explore whether near-future warming scenarios are likely to affect the efficacy of Wolbachia-based biocontrol. The models combine empirical estimates of thermal sensitivity for one strain of Wolbachia with projections of future average temperatures and heatwaves for Cairns, Australia and Nha Trang City, Vietnam, two locations where the intervention has been deployed. Estimates of the bacterium’s successful persistence in the mosquito population remain high under tested projections of moderate and severe average warming to 2050. However, the simulations also show reduced efficacy under more variable thermal extremes; these interventions have the potential to fail under extreme warming with long heatwave durations. We selected this paper for our Year in Review collection because it exemplifies how insect thermal biology and global change analysis can offer insights relevant to human health. Testing whether climate change influences Wolbachia-based biocontrol helps to illuminate whether the promising technology is likely to remain feasible in coming years.
Gene drives – maybe not a silver bullet, but a bullet nonetheless
28745Jenny Leonard, New Zealand's Biological Heritage, 2023-12-20 15:26:56.
A gene drive is both a natural process and a genetic engineering technology where a gene is promoted or favoured during reproduction—instead of there being a “chance” of an offspring inheriting a gene, gene drives almost guarantee that the offspring (and subsequent offspring) will inherit that gene. The common wasp, Vespula vulgaris, is driving a lot of unwanted change in Aotearoa in the form of damaging our native ecosystems. Could genetic engineering drive country-wide eradication? A new paper uses modelling to show that eradication would probably be very difficult to achieve—but the paper also shows that a wasp gene drive could still make a significant difference in getting populations to a manageable level. In New Zealand, gene drives may be a solution for managing pests like the invasive social wasp (Vespula vulgaris). “We know we can target several genes that would stop sperm development within wasps,” says Phil Lester, a professor at Te Herenga Waka – Victoria University of Wellington and co-lead of Novel Tools & Strategies – Invertebrates.
Rapid turnover of pathogen-blocking Wolbachia and their incompatibility loci
28733Shropshire JD, Conner WR, Vanderpool D, Hoffmann AA, Turelli M, Cooper BS., bioRxiv, 2023-12-19 16:02:29.
At least half of all insect species carry maternally inherited Wolbachia alphaproteobacteria, making Wolbachia the most common endosymbionts in nature. Wolbachia spread to high frequencies is often due to cytoplasmic incompatibility (CI), a Wolbachia -induced sperm modification that kills embryos without Wolbachia . Several CI-causing Wolbachia variants, including w Mel from Drosophila melanogaster , also block viruses. Establishing pathogen-blocking w Mel in natural Aedes aegypti mosquito populations has reduced dengue disease incidence, with one study reporting about 85% reduction when w Mel frequency is high. However, w Mel transinfection establishment is challenging in many environments, highlighting the importance of identifying CI-causing Wolbachia variants that stably persist in diverse hosts and habitats. We demonstrate that w Mel-like variants have naturally established in widely distributed holometabolous dipteran and hymenopteran insects that diverged approximately 350 million years ago, with w Mel variants spreading rapidly among these hosts over only the last 100,000 years. Wolbachia genomes contain prophages that encode CI-causing operons ( cifs ). These cifs move among Wolbachia genomes - with and without prophages - even more rapidly than Wolbachia move among insect hosts. Our results shed light on how rapid host switching and horizontal gene transfer contribute to Wolbachia and cif diversity in nature. The diverse w Mel variants we report here from hosts present in different climates offer many new options for broadening Wolbachia -based biocontrol of diseases and pests.
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.
Current Status of the Main Olive Pests: Useful Integrated Pest Management Strategies and Genetic Tools
28380E. Lantero, B. Matallanas and C. Callejas, Applied Sciences, 13. 2023-11-06 09:55:38.
Mediterranean olive cultivation faces challenges in the global environmental change context. Pests and diseases caused by arthropods such as Bactrocera oleae, Prays oleae, and certain vectors of Xylella fastidiosa are expected to increase and spread in part due to this global scenario. The control of these arthropods has relied on synthetic pesticides, the misuse of which has led to pest population resistance and concerns about their negative impacts on biodiversity and global health. Integrated pest management (IPM) methods have emerged through the careful consideration of all available control techniques and the subsequent integration of appropriate measures that discourage the development of pest populations. This paper reviews the IPM guidelines for olive cultivation, prioritizing the use of biological control methods, and the integration of genetics and biotechnology, which bring precision, efficacy, and safety. It evidences the importance of genetic analysis in pest populations, pesticide resistance and in the contributions of predators to pest control. Advances in formulations and delivery systems for pesticides such as Bacillus thuringiensis, plant-incorporated protectants, improved SIT techniques, and the specific efficacy of biologicals pesticides are covered. Finally, this paper explores promising tools such as RNAi and gene drive while recognizing the ethical, environmental, and regulatory challenges associated with their use. Shortly, these innovations have the potential to reduce the environmental impacts of pests while ensuring the long-term viability of the olive industry.
Biotechnological Potential of Microorganisms for Mosquito Population Control and Reduction in Vector Competence
28272R. D. Katak, A. M. Cintra, B. C. Burini, O. Marinotti, J. A. Souza-Neto and E. M. Rocha, Insects, 14. 2023-10-30 07:59:35.
Mosquitoes transmit pathogens that cause human diseases such as malaria, dengue fever, chikungunya, yellow fever, Zika fever, and filariasis. Biotechnological approaches using microorganisms have a significant potential to control mosquito populations and reduce their vector competence, making them alternatives to synthetic insecticides. Ongoing research has identified many microorganisms that can be used effectively to control mosquito populations and disease transmission. However, the successful implementation of these newly proposed approaches requires a thorough understanding of the multipronged microorganism-mosquito-;pathogen-environment interactions. Although much has been achieved in discovering new entomopathogenic microorganisms, antipathogen compounds, and their mechanisms of action, only a few have been turned into viable products for mosquito control. There is a discrepancy between the number of microorganisms with the potential for the development of new insecticides and/or antipathogen products and the actual available products, highlighting the need for investments in the intersection of basic research and biotechnology.
Effect of the Sterile Insect Technique and Augmentative Parasitoid Releases in a Fruit Fly Suppression Program in Mango-Producing Areas of Southeast Mexico
27989J. Cancino, P. Montoya, F. O. Gálvez, C. Gálvez and P. Liedo, Insects, 14. 2023-08-22 08:09:28.
The Sterile Insect Technique (SIT), by means of sterile male releases of Anastrepha ludens (Loew), coupled with Augmentative Biological Control (ABC), by releasing the parasitoid Diachasmimorpha longicaudata (Ashmead), was evaluated in a commercial mango production area for one year. The obtained results were compared with mean fruit fly population values from two previous years without the combined use of both techniques. The treatments were: SIT + ABC, SIT, ABC, and Control, and each treatment was established in blocks of 5000 Ha separated by distances of 5–10 km. The evaluations were carried out through fruit sampling to assess percent parasitism and trapping of adult flies to obtain Flies per Trap per Day (FTD) values. The mean percentage of parasitism increased from 0.59% in the control treatment to 19.38% in the block with ABC. The FTD values decreased from ~0.129 and ~0.012 in the control block to 0.0021 in the block with SIT and ABC, representing a 98% suppression. The difference between the two periods in the control block was not significant. We conclude that the integration of both techniques resulted in an additive suppression of the pest population, supporting the use of both control techniques in an area-wide pest management context.
A rapidly spreading deleterious aphid endosymbiont that uses horizontal as well as vertical transmission
25082X. Gu, P. A. Ross, A. Gill, Q. Yang, E. Ansermin, S. Sharma, S. Soleimannejad, K. Sharma, A. Callahan, C. Brown, P. A. Umina, T. N. Kristensen and A. A. Hoffmann, Proceedings of the National Academy of Sciences, 120:e2217278120. 2023-04-24 06:34:04.
Endosymbiotic bacteria that live inside the cells of insects are typically only transmitted maternally and can spread by increasing host fitness and/or modifying reproduction in sexual hosts. Transinfections of Wolbachia endosymbionts are now being used to introduce useful phenotypes into sexual host populations, but there has been limited progress on applications using other endosymbionts and in asexual populations. Here, we develop a unique pathway to application in aphids by transferring the endosymbiont Rickettsiella viridis to the major crop pest Myzus persicae. Rickettsiella infection greatly reduced aphid fecundity, decreased heat tolerance, and modified aphid body color, from light to dark green. Despite inducing host fitness costs, Rickettsiella spread rapidly through caged aphid populations via plant-mediated horizontal transmission. The phenotypic effects of Rickettsiella were sensitive to temperature, with spread only occurring at 19 °C and not 25 °C. Body color modification was also lost at high temperatures despite Rickettsiella maintaining a high density. Rickettsiella shows the potential to spread through natural M. persicae populations by horizontal transmission and subsequent vertical transmission. Establishment of Rickettsiella in natural populations could reduce crop damage by modifying population age structure, reducing population growth and providing context-dependent effects on host fitness. Our results highlight the importance of plant-mediated horizontal transmission and interactions with temperature as drivers of endosymbiont spread in asexual insect populations.
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.
The Effect of the Sterile Insect Technique on Vibrational Communication: The Case of Bagrada hilaris (Hemiptera: Pentatomidae)
24951C. Peccerillo, C. E. Mainardi, R. Nieri, J. M. Fouani, A. Cemmi, M. Cristofaro, G. Anfora and V. Mazzoni, Insects, 14. 2023-04-02 13:09:28.
The painted bug, Bagrada hilaris, is an agricultural pest in its original areas (Africa, South Asia, and the Middle East), and it has recently been recorded as an invasive species in southwestern part of the US, Chile, Mexico, and two islands in the Mediterranean basin. Its polyphagous diet causes severe damage to economically important crops. The control of this pest is primarily achieved by means of synthetic pesticides, which are often expensive, ineffective, and harmful to the ecosystem. Recent physiological bioassays to assess its potential control through the sterile insect technique demonstrated that mating between untreated females and males irradiated at doses of 64 and 100 Gy, respectively, resulted in 90% and 100% sterility of the eggs produced by the females. In this study, the mating abilities of virgin males irradiated at 60 and 100 Gy with virgin females were measured through a study of short-range courtship mediated by vibrational communication. The results indicate that males irradiated at 100 Gy emit signals with lower peak frequencies, mate significantly less than unirradiated males do, and do not surpass the early stages of courtship. Conversely, males irradiated at 60 Gy present vibrational signal frequencies that are comparable to those of the control and successfully mated males. Our findings suggest that B. hilaris individuals irradiated at 60 Gy are good candidates for the control of this species, given that they retain sexual competitiveness regardless of their sterility, through an area-wide program that incorporates the sterile insect technique.
Additive Effect of Releasing Sterile Insects Plus Biocontrol Agents against Fruit Fly Pests (Diptera: Tephritidae) under Confined Conditions
24928P. Montoya, E. Flores-Sarmiento, P. López, A. Ayala and J. Cancino, Insects, 14. 2023-03-30 13:54:53.
Pest control models integrating the use of the sterile insect technique (SIT) and augmentative biological control (ABC) have postulated that it is possible to obtain a synergistic effect from the joint use of these technologies. This synergistic effect is attributed to the simultaneous attack on two different biological stages of the pest (immature and adult flies), which would produce higher suppression on the pest populations. Here we evaluated the effect of the joint application of sterile males of A. ludens of the genetic sexing strain Tap-7 along with two parasitoid species at the field cage level. The parasitoids D. longicaudata and C. haywardi were used separately to determine their effect on the suppression of the fly populations. Our results showed that egg hatching percentage was different between treatments, with the highest percentage in the control treatment and a gradual reduction in the treatments with only parasitoids or only sterile males. The greatest induction of sterility (i.e., the lowest egg hatching percentage) occurred with the joint use of ABC and SIT, demonstrating that the earlier parasitism caused by each parasitoid species was important reaching high levels of sterility. Gross fertility rate decreased up to 15 and 6 times when sterile flies were combined with D. longicaudata and C. haywardi, respectively. The higher parasitism by D. longicaudata was determinant in the decrease of this parameter and had a stronger effect when combined with the SIT. We conclude that the joint use of ABC and SIT on the A. ludens population had a direct additive effect, but a synergistic effect was observed in the parameters of population dynamics throughout the periodic releases of both types of insects. This effect can be of crucial importance in the suppression or eradication of fruit fly populations, with the added advantage of the low ecological impact that characterizes both techniques.
Biological comparative study between Wolbachia-infected Aedes aegypti mosquito and Wolbachia-uninfected strain, Jeddah city, Saudi Arabia
24804A. G. Algamdi, F. M. Shaher and J. A. Mahyoub, Saudi J Biol Sci, 30:103581. 2023-02-02 08:32:08.
In this study, samples of Wolbachia-infected Aedes aegypti mosquitoes were collected from Al-Safa district in Jeddah city, Saudi Arabia. The presence of Wolbachia bacteria in mosquitoes was confirmed by PCR technique and they were reared and propagated in the laboratory. Comparative studies were conducted between Wolbachia-infected A. Aegypti and the Wolbachia-uninfected laboratory strain in terms of their ability to withstand drought, resist two types of insecticides and the activities of pesticide detoxification enzymes. The Wolbachia-infected A. aegypti strain proved less able to withstand the drought period, as the egg-hatching rate of the Wolbachia-uninfected strain was greater than that of the Wolbachia-infected strain after one, two and three months of dry periods. Compared to the Wolbachia-uninfected strain, the Wolbachia-infected strain demonstrated a relatively greater resistance to tested pesticides, namely Baton 100EC and Fendure 25EC which may be attributed to the higher levels of the detoxification enzymes glutathione-S-transferase and catalase and the lower levels of esterase and acetylcholine esterase.
Control of Aedes mosquito populations using recombinant microalgae expressing short hairpin RNAs and their effect on plankton
24615X. Fei, S. Xiao, X. Huang, Z. Li, X. Li, C. He, Y. Li, X. Zhang and X. Deng, PLOS Neglected Tropical Diseases, 17:e0011109. 2023-01-26 09:15:48.
New biocontrol strategies are urgently needed to combat vector-borne infectious diseases. This study presents a low-cost method to produce a potential mosquito insecticide that utilizes the microalgae released into suburban water sources to control mosquito populations. Chlorella microalgae are ubiquitous in local waters, which were chosen as the host for genetic transfection. This species facilitated the recombinant algae to adapt to the prevailing environmental conditions with rapid growth and high relative abundance. The procedure involved microalgae RNAi-based insecticides developed using short hairpin RNAs targeting the Aedes aegypti chitin synthase A (chsa) gene in Chlorella. These insecticides effectively silenced the chsa gene, inhibiting Aedes metamorphosis in the laboratory and simulatedfield trials. This study explored the impact of recombinant microalgae on the phytoplankton and zooplankton in suburban waters. High-throughput sequencing revealed that rapid reproduction of recombinant Chlorella indirectly caused the disappearance of some phytoplankton and reduced the protozoan species. This study demonstrated that a recombinant microalgae-based insecticide could effectively reduce the population of Aedes mosquitoes in the laboratory and simulated field trials. However, the impact of this technology on the environment and ecology requires further investigation.
The suppressive potential of a gene drive in populations of invasive social wasps is currently limited
23091A. B. Meiborg, N. R. Faber, B. A. Taylor, B. A. Harpur and G. Gorjanc, bioRxiv, 2022.06.27.497711. 2022-06-30 07:33:43.
Social insects are very successful invasive species, and the continued increase of global trade and transportation has exacerbated this problem. The yellow-legged hornet, Vespa velutina nigrithorax (henceforth Asian hornet), is drastically expanding its range in Western Europe. As an apex insect predator, this hornet poses a serious threat to the honey bee industry and endemic pollinators. Current suppression methods have proven too inefficient and expensive to limit its spread. Gene drives might be an effective tool to control this species, but their use has not yet been thoroughly investigated in social insects. Here, we built a model that matches the hornet’s life history and modelled the effect of different gene drive scenarios on an established invasive population. To test the broader applicability and sensitivity of the model, we also incorporated the invasive European paper wasp Polistes dominula. We find that although a gene drive can spread through a social wasp population, it can only do so under stringent gene drive-specific conditions. The main issue is that the large number of offspring that social wasp colonies produce guarantees that, even with very limited formation of resistance alleles, such alleles will quickly spread and rescue the population. Furthermore, we find that only a gene drive targeting female fertility is promising for population control due to the haplodiploidy of social insects. Nevertheless, continued improvements in gene drive technology may make it a promising method for the control of invasive social insects.Competing Interest StatementThe authors have declared no competing interest.
Rescue by gene swamping as a gene drive deployment strategy
20587K. D. Harris and G. Greenbaum, bioRxiv, 2022.03.08.483503. 2022-03-08 11:25:49.
Gene drives are genetic constructs that can spread deleterious alleles with potential application to population suppression of harmful species. Given that a gene drive can potentially spill over to other populations or even other species, control measures and fail-safes strategies must be considered. Gene drives are designed to generate a rapid demographic decline, while at the same time generating a dynamic change in the population’s genetics. Since these evolutionary and demographic processes are linked and are expected to occur at a similar time-scale during gene drive spread, feedback between these processes may significantly affect the outcome of deployment. To study this feedback and to understand how it affects gene drive spillovers, we developed a gene drive model that combines evolutionary and demographic dynamics in a two-population setting. The model demonstrates how feedback between evolutionary and demographic dynamics can generate additional outcomes to those generated by the evolutionary dynamics alone. We identify an outcome of particular interest, where the short-term suppression of the target population is followed by gene swamping and loss of the gene drive. This outcome could be useful for designing gene drive deployments that temporarily suppress the population, but ultimately do not remain in the population. Using our model, we demonstrate the robustness of this outcome to spillover and to the evolution of resistance, and suggest that it could be used as a fail-safe strategy for gene drive deployment.Competing Interest StatementThe authors have declared no competing interest.
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.
The Possible Role of Microorganisms in Mosquito Mass Rearing
17741L. Chersoni, A. Checcucci, M. Malfacini, A. Puggioli, F. Balestrino, M. Carrieri, I. Piunti, M. L. Dindo, P. Mattarelli and R. Bellini, Insects, 12. 2021-07-15 13:10:37.
In Europe, one of the most significant mosquitoes of public health importance is Aedes albopictus (Skuse), an allochthonous species of Asian origin. One of the most promising control methods against Aedes albopictus is the sterile insect technique (SIT), which consists of mass rearing the target species, separation of males from females, and male exposure to sterilizing ionizing radiation. Once released in the environment, the sterile males are expected to search for wild females to mate with. If mating occurs, no offspring is produced. The quality of sterile males is a crucial aspect in SIT programs in order to optimize effectiveness and limit production costs. The integration of probiotic microorganisms in larval and adult mosquito diets could enhance the quality parameters of the released sterile males. In this review, we attempt to give the most representative picture of the present knowledge on the relationships between gut microbiota of mosquitoes and the natural or artificial larval diet. Furthermore, the possible use of probiotic microorganisms for mosquito larvae rearing is explored. Based on the limited amount of data found in the literature, we hypothesize that a better understanding of the interaction between mosquitoes and their microbiota may bring significant improvements in mosquito mass rearing for SIT purposes.
Cloning wildlife and editing their genes to protect them and us.
16982H. Thomasy, NEO-LIFE, 2021-05-06 16:06:20.
In December 10, 2020, Elizabeth Ann made history just by being born. She isn’t a British royal, an American married to a British royal, a movie star’s daughter, or even human for that matter. Elizabeth Ann is a ferret—but perhaps the most famous ferret of all time. More specifically, she is the clone of a black-footed ferret named Willa who has been dead for more than 30 years. Elizabeth Ann’s momentous birth marks the first successful cloning of an endangered species native to North America (endangered species like the gaur, or Indian bison, and the mouflon, a wild sheep originally found in Corsica and Sardinia, have been cloned previously). If she can breed successfully, Elizabeth Ann will add valuable genetic diversity to the very small estimated population of around 600 remaining black-footed ferrets, which are all descended from just seven animals. But low genetic diversity isn’t the only thing standing in the way of these ferrets making a comeback. The other major threat is disease. Diseases are a huge problem for many endangered species, but, as the previous year has emphasized all too well, diseases that circulate in animals can also have disastrous consequences if they jump to humans. Genetic engineering of animals in the wild might offer us a way to protect not only our furry friends and feathered compadres, but ourselves as well. Although still in the early stages of research, scientists around the world are working on numerous projects to engineer animals to be resistant to diseases that can impact humans as well, including plague, Lyme disease, dengue fever, and Zika.
Evaluating unintended consequences of intentional species introductions and eradications for improved conservation management
16631D. E. Pearson, T. J. Clark and P. G. Hahn, Conserv Biol, 2021-03-19 14:52:01.
We conducted a global literature review of these conservation actions to quantify how often unintended outcomes occur and to elucidate their underlying causes. We found that studies reported intended outcomes in 51% of cases, a combination of intended outcomes and unintended outcomes in 26% of cases, and strictly unintended outcomes in 10% of cases. Hence, unintended outcomes were reported in 36% of all cases evaluated. In evaluating overall conservations outcomes (weighing intended vs unintended effects), some unintended effects are fairly innocuous relative to successful conservation objectives whereas others result in serious unintended consequences in recipient communities. Importantly, we also found that studies that assessed a greater number of community interactions with the target species were more likely to report unintended outcomes, suggesting that unintended consequences may be under-reported due to insufficient vetting.
A patent review on strategies for biological control of mosquito vector
15377K. Parihar, M. Telang and A. Ovhal, World Journal of Microbiology and Biotechnology, 36:23. 2020-12-09 20:28:33.
This paper presents a comprehensive technology overview of patent documents disclosing biological agents for mosquito control. The patent analysis revealed that comparable number of patent documents were filed in two technology categories: non-recombinant agents and genetically modified (GM) agents. In the category of non-recombinant agents, toxic peptides from microbes and biological consortia seemed to be the earliest technology noted right from the year 1965 whereas the patent filings for suppression of mosquito population using genetic modification techniques have emerged from the year 2000 onwards. The United States of America is the leading patent filing jurisdiction followed by China and the Great Britain. Academic institutes have filed higher number of patent applications as compared to private companies. University of Florida was found to be the leading patent filing entity and its patents were focused on suppression of vector population using techniques such as release of insects with dominant lethal (RIDL) and RNA interference (RNAi).
Maintenance management and eradication of established aquatic invaders
13936D. Simberloff, Hydrobiologia, 22. 2020-08-06 13:34:15.
The rapid development of technologies based on genetics has engendered excitement about possibly eradicating or controlling terrestrial invaders, and such technologies may also prove useful for certain aquatic invaders. Methods of particular interest, alone or in various combinations, are gene-silencing, RNA-guided gene drives, and the use of transgenes.
The value of existing regulatory frameworks for the environmental risk assessment of agricultural pest control using gene drive
8194J. Romeis, J. Collatz, D. C. M. Glandorf and M. B. Bonsall, Environmental Science & Policy, 108:19-36. 2020-03-27 20:20:04.
The application of (synthetic) gene drives is a powerful tool to control populations of insects that are agricultural pests, vectors of diseases, or a threat to biodiversity potentially leading to the local or global eradication of a species. The potential use of gene drive organisms has triggered a heated discussion regarding their environmental impacts and regulatory oversight. However, experience exists in assessing the environmental impacts of a number of established agricultural pest control methods that require the release of living organisms, that provide high levels of area-wide control and that might be irreversible. This includes classical biological control, the sterile insect technique, the incompatible insect technique that is based on the cytoplasmic incompatibility caused by Wolbachia endosymbionts, and genetically modified insects containing self-limiting traits. The different technologies are described, the regulatory practice and experience is summarized and pathways through which these control technologies could harm valued ecosystem services are presented. With a focus on the application of gene drives in agriculture, using the invasive Drosophila suzukii (Diptera: Drosophilidae) as a case study we then discuss to what extent the existing frameworks could assist the risk assessment of insects carrying gene drives. We suggest that drawing on existing practices, experiences and legislative frameworks will provide a pragmatic and proportionate approach to evaluate the environmental risks of novel solutions based on gene drive technologies.
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.
Optimal control and analysis of a modified trojan Y-Chromosome strategy
11491M. A. Beauregard, R. D. Parshad, S. Boon, H. Conaway, T. Griffin and J. J. Lyu, Ecological Modelling, 416. 2020-01-15 20:19:52.
The Trojan Y Chromosome (TYC) strategy is a promising eradication method that attempts to manipulate the female to male ratio to promote the reduction of the population of an invasive species. The manipulation stems from an introduction of sex-reversed males, called supermales, into an ecosystem. The offspring of the supermales is guaranteed to be male. Mathematical models have shown that the population can be driven to extinction with a continuous supply of supermales. In this paper, a new model of the TYC strategy is introduced and analyzed that includes two important modeling characteristics, that are neglected in all previous models. First, the new model includes intraspecies competition for mates. Second, a strong Allee effect is included. Several conclusions about the strategy via optimal control are established. These results have large scale implications for the biological control of invasive species.
CRISPR gene drive efficiency and resistance rate is highly heritable with no common genetic loci of large effect
3901Champer, JW, Z. X.; Luthra, A.; Reeves, R.; Chung, J.; Liu, C.; Lee, Y. L.; Liu, J. X.; Yang, E.; Messer, P. W.; Clark, A. G., Genetics, 212:333-341. 2019-01-19 00:00:00.
Gene drives could allow for control of vector-borne diseases by directly suppressing vector populations or spreading genetic payloads designed to reduce pathogen transmission. Clustered regularly interspaced short palindromic repeat (CRISPR) homing gene drives work by cleaving wild-type alleles, which are then converted to drive alleles by homology-directed repair, increasing the frequency of the drive in a population over time. However, resistance alleles can form when end-joining repair takes place in lieu of homology-directed repair. Such alleles cannot be converted to drive alleles, which would eventually halt the spread of a drive through a population. To investigate the effects of natural genetic variation on resistance formation, we developed a CRISPR homing gene drive in Drosophila melanogaster and crossed it into the genetically diverse Drosophila Genetic Reference Panel (DGRP) lines, measuring several performance parameters. Most strikingly, resistance allele formation postfertilization in the early embryo ranged from 7 to 79% among lines and averaged 42 +/- 18%. We performed a genome-wide association study using our results in the DGRP lines, and found that the resistance and conversion rates were not explained by common alleles of large effect, but instead there were several genetic polymorphisms showing weak association. RNA interference knockdown of several genes containing these polymorphisms confirmed their effect, but the small effect sizes imply that their manipulation would likely yield only modest improvements to the efficacy of gene drives.
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.
Invasion Success and Management Strategies for Social Vespula Wasps
13740P. J. Lester and J. R. Beggs, Annual Review of Entomology, 64:51-71. 2018-09-26 19:38:03.
Three species of Vespula have become invasive in Australia, Hawai'i, New Zealand, and North and South America and continue to spread. Economically, their main negative effect is associated with pollination and the apicultural industry. Climate change is likely to exacerbate their impacts in many regions. Although investigated extensively, no effective biological control agents have yet been found. Emerging technologies such as gene drives are under consideration.
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.
Ecological and evolutionary applications for environmental sex reversal of fish
11518A. McNair, P. M. Lokman, G. P. Closs and S. Nakagawa, Quarterly Review of Biology, 90:23-44. 2015-03-01 15:38:29.
Environmental sex reversal (ESR), which results in a mismatch between genotypic and phenotypic sex, is well documented in numerous fish species and may be induced by chemical exposure. Historically, research involving piscine ESR has been carried out with a view to improving profitability in aquaculture or to elucidate the processes governing sex determination and sexual differentiation. However, recent studies in evolution and ecology suggest research on ESR now has much wider applications and ramifications. We begin with an overview of ESR in fish and a brief review of the traditional applications thereof We then discuss ESR and its potential demographic consequences in wild populations. Theory even suggests sex-reversed fish may be purposefully released to manipulate population dynamics. We suggest new research directions that may prove fruitful in understanding how ESR at the individual level translates to population-level processes. In the latter portion of the review we focus on evolutionary applications of ESR Sex-reversal studies from the aquaculture literature provide insight in to the evolvability of determinants of sexual phenotype. Additionally, induced sex reversal can provide information about the evolution of sex chromosomes and sex-linked traits. Recently, naturally occurring ESR has been implicated as a mechanism contributing to the evolution of sex chromosomes.
Genetic control of invasive fish: technological options and its role in integrated pest management
4158Thresher, REH, K.; Bax, N. J.; Teem, J.; Benfey, T. J.; Gould, F., Biological Invasions, 16:1201-1216. 2014-01-16 00:00:00.
Genetic options for the control of invasive fishes were recently reviewed and synthesized at a 2010 international symposium, held in Minneapolis/St. Paul, MN, USA. The only option currently available "off-the-shelf'' is triploidy, which can be used to produce sterile males for a release program analogous to those widely and successfully used for biological control of insect pests. However, the Trojan Y and several recombinant options that heritably distort pest population sex ratios are technologically feasible, are at or are close to proof-of-concept stage and are potentially much more effective than sterile male release programs. All genetic options at this stage require prolonged stocking programs to be effective, though gene drive systems are a potential for recombinant approaches. They are also likely to differ in their current degree of social acceptability, with chromosomal approaches (triploidy and Trojan Y) likely to be the most readily acceptable to the public and least likely to require changes in legislative or policy settings to be implemented. Modelling also suggests that the efficacy of any of these genetic techniques is enhanced by, and in turn non-additively enhance, conventional methods of pest fish control.
Requirements for effective malaria control with homing endonuclease genes
4203Deredec, AG, H. C. J.; Burt, A., Proceedings of the National Academy of Sciences of the United States of America, 108:e874-e880. 2011-01-21 00:00:00.
Malaria continues to impose a substantial burden on human health. We have previously proposed that biological approaches to control the mosquito vector of disease could be developed using homing endonuclease genes (HEGs), a class of selfish or parasitic gene that exists naturally in many microbes. Recent lab studies have demonstrated that HEGs can function in mosquitoes. We constructed and analyzed a model of mosquito population genetics and malaria epidemiology to determine how well HEGs need to function in order to have a significant effect on the burden of disease. Our model, combined with currently available data, indicates that populations of Anopheles gambiae could be eliminated by releasing 2-3 HEGs targeting female fertility genes, or a driving-Y chromosome that is transmitted to 75-96% of progeny. Combinations of fertility-targeting HEGs and Y drive may also be effective. It is possible to eliminate the disease without eliminating the vector, but the parameter space producing this outcome appears to be small. HEGs causing a quantitative reduction in adult survival can be more effective than those targeting female fertility, but the selection coefficients that need to be imposed are still large, unless many HEGs are to be released. Simulations show that HEG-based strategies can be effective over socially relevant time frames. Important limiting assumptions of the models are that there is only a single vector species, and we model a homogeneous population, not a landscape. Nevertheless, we conclude that HEG-based approaches could have a transformational effect on malaria control efforts.
Guidelines for the export, shipment, import and release of biological control agents and other beneficial organisms
16037International Plant Protection Convention, Food and Agriculture Organization, 2005-04-01 19:55:50.
This standard provides guidelines for risk management related to the export, shipment, import and release of biological control agents and other beneficial organisms. It lists the related responsibilities of contracting parties to the IPPC, national plant protection organizations (NPPOs) or other responsible authorities, importers and exporters (as described in the standard). The standard addresses biological control agents capable of self-replication (including parasitoids, predators, parasites, nematodes, phytophagous organisms, and pathogens such as fungi, bacteria and viruses), as well as sterile insects and other beneficial organisms (such as mycorrhizae and pollinators), and includes those packaged or formulated as commercial products.
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