Location: Agroecosystem Management Research2022 Annual Report
OBJECTIVE 1: Determine the environmental predictors of stable fly outbreaks and dispersal. Subobjective 1A: Identify and model environmental variates associated with stable fly population dynamics. Subobjective 1B: Model stable fly population dynamics in differing climatic zones. OBJECTIVE 2: Investigate stable fly larval habitats to develop improved management strategies that protect livestock from stable flies. Subobjective 2A: Characterize the temporal and spatial dynamics of physical and biological parameters associated with stable fly developmental substrates. Subobjective 2B: Identify and develop stable fly larvicides and assess their sustainability. OBJECTIVE 3: Identify stable fly attractants and repellents for use in strategies to protect livestock from stable flies. Subobjective 3A: Identify novel stable fly attractant compounds from host animals and larval development sites (substrates). Subobjective 3B: Develop long acting formulations with spatial and contact repellency. Subobjective 3C: Identify and develop novel stable fly oviposition deterrents. Subobjective 3D: Incorporate products developed in 3A-3C into a comprehensive Push-Pull strategy for managing stable fly infestations and improving animal well-being.
Stable flies are among the most important arthropod pests of livestock and, with changing climate and agronomic practices, are poised to expand their roles as pests and disease vectors. Their painful bites reduce livestock productivity, annoy companion animals, and interfere with recreational activities. Recent estimates of the economic impact of stable flies on cattle industries in the United States exceed $2 billion. Current management technologies are unable to effectively manage stable flies. This project proposes to address the development of novel technologies for managing stable fly populations and their impact on livestock using basic and applied research. Basic research will address developmental biology and population dynamics. Applied research includes chemical control strategies, repellants for protecting animals, and attractants for improving the efficacy of trapping devices. Combined, these efforts will improve our ability to monitor stable fly populations, identify and manage larval developmental substrates, and protect livestock from their painful bites. Successful completion of this project will improve livestock productivity and producer’s profits, as well as reduce livestock stress and disease.
Progress has been made in all subobjectives of Objective #3 with new discoveries in furthering technology transfer development in biting fly management. New attractants (e.g., 2-phenylethanol) were identified from recently reported stable fly associated environments (post-harvest pineapple residues and sugarcane produced ethanol byproduct) and were further demonstrated with behavioral activity under laboratory assay (Sub-objective 3A). Repellent blends consisting of coconut oil fatty acids were formulated in a starch-pectin water-based sprayable solution, tested, and demonstrated with strong repellency to deter biting flies that attack livestock animals, with over 95% prevention of blood-feeding in laboratory assays. Preliminary results conducted in a pasture cattle experimental farm showed equal or better control in efficacy against stable flies compared to traditional pesticide application, permethrin (Sub-objective 3B). The significant findings of the strong repellent activity and relatively long effectiveness from coconut medium chain fatty acids have further expanded the research to collaborations with scientists in universities and industries to develop efficient plant-based human skin repellent lotions, applications in U.S. military uniforms against mosquitoes and other blood-sucking insect pests, as well as some agricultural and urban pests. Strong ovipositional inhibition was also demonstrated in laboratory bioassays which showed over 90% reduction in stable fly egg-laying in media treated with these acid compounds derived from coconut oil. A formulation containing 15% of acid contents tested in the field in Costa Rica showed a significant reduction in larvae found from the post-harvest pineapple field, compared to the control field where no treatment was sprayed (Sub-objective 3C). Push-pull field trials conducted with a modified cylinder trapping system equipped with a 1-mg dose of m-cresol (attractant) and a topical application of 500ml (per cattle) of starch-pectin formulation containing 6.7% (wt%) coconut fatty acids showed a significant reduction in the number of stable fly attacks on cattle within treatment groups, compared to the untreated control groups (Sub-objective 3D). The effectiveness from the push-pull strategy in reducing stable flies was similar to the level of control of the permethrin treated cattle. For Objective 2, the coconut fatty acid based repellent formulation investigated in Objective 3 demonstrated unexpected larvicidal activity both in laboratory and field trials.
1. Insect tape trap and attractant added adhesive glue. ARS scientists in Lincoln, Nebraska, have identified novel attractant compounds that can be used to reduce stable fly attack leading to annual economic losses more than $2 billion to the U.S. cattle industry. A U.S. patent has been granted (US 2022/0015348 A1, Jan. 20, 2022). The developed prototype products include an attractant impregnated adhesive glue and tape that have been sought by pest control professionals from several countries.
2. Long-lasting coconut fatty acid repellent formulations against blood-sucking insects. Repellent application is a useful tool to keep disease vectors away from human beings and is considered one of the most effective ways to reduce nuisance and vector mosquito bites. DEET is the most effective repellent, however the negative reports of DEET’s impact on human health have reduced public acceptance of its use. ARS researchers in Lincoln, Nebraska, together with their U.S. small business partners in Ohio and South Carolina, developed a prototype coconut oil fatty acid mosquito repellent lavender oil-based lotion with demonstrated efficacy better than DEET, and impregnated repellent compounds onto U.S. soldier’s uniform for vector and disease prevention.
Barrozo, M.M., Zeringóta, V., Boreges, L.M., Moraes, N., Benz, K., Farr, A., Zhu, J.J. 2021. Repellent and acaricidal activity of coconut oil fatty acids and their derivative compounds against Amblyomma sculptum. Veterinary Parasitology. https://doi.org/10.1016/j.vetpar.2021.109591.
Luo, D., Yan, Z., Che, L., Chen, B., Zhu, J.J. 2022. Repellency and insecticidal activity of seven Mugwort (Artemisia argyi) essential oils against the malaria vector Anopheles sinensis. Scientific Reports. https://doi.org/10.1038/s41598-022-09190-0.
Wang, F., Shen, Z., Schal, C., Zhu, J.J., Zhou, G., Wang, Y., Wang, J., Deng, J., Wan, N. 2021. Pheromone antagonism in Plutella xylostella (Linnaeus) by sex pheromones of two sympatric noctuid moths. Pest Management Science. 78(1):379-387. https://doi.org/10.1002/ps.6651.