Location: Agroecosystem Management Research
2023 Annual Report
Objectives
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.
Approach
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 Report
All milestones in Objective 3 were met completely, with several additional findings that help develop better strategies for managing the biting fly attack on cattle, reducing their stress significantly. The new stable fly bait contained 2-phenylethanol identified from a different stable fly larval development has demonstrated a better attractiveness to stable flies with strong background odors of cattle manure, which are also part of our previously identified attractants. Preliminary field results showed that topical applications of the starch-pectin water-based coconut fatty acid formulation on cattle can provide over 5 days of protection against stable fly attack in pasture settings for consecutive years’ field trials. This effectiveness is comparable with the synthetic permethrin application, but with a significantly lower cost for materials used in formulation development. Several other formulations using lavender oil, mineral oil, and other skin lotions with two fatty acids (decanoic and dodecanoic acid, either individual or blends) provide effective protection for humans against mosquito, tick, and bedbug biting. These formulations were also effective repellents against some urban pests such as scorpions and cockroaches. The water-based repellent formulation performed well on cattle and can also effectively deter stable fly oviposition. Additional tests using the two acids’ derivatives including methyl esters also showed oviposition deterrence. Our push-pull trials conducted in Northern Nebraska on pasture cattle have shown a significant reduction of stable fly attack on cows treated with the coconut fatty acid formulation. However, a pull strategy using the m-cresol baited Knight sticky trap system needs to be further improved next year.
For Objective 2A, to characterize the temporal and spatial dynamics of physical and biological parameters associated with stable fly developmental substrates, we have collected substrates of stable fly larvae development sites including the 3rd instar larvae from three locations in Nebraska (Mead, Clay Center, and North Platte). The gut contents of the 3rd instar larvae have been dissected, processed and are ready for further analysis. The substrates from three locations were also collected and stored for DNA preparation and further sequencing analysis. The DNA from both gut contents and larval substrates will be submitted for shotgun sequencing for a microbial community composition study.
Accomplishments
1. First successful field trial on cattle using the push-pull strategy battling stable flies. Stable fly attacks on livestock animals cost U.S. cattle producers over 2 billion dollars in losses annually. Current control methods involve massive pesticide applications that have shown limited effectiveness and increase resistance. ARS scientists in Lincoln, Nebraska, developed a new push-pull strategy using a natural product repellent formulation and a naturally occurring attractant compound associated with cattle that provides a similar level of effectiveness in reducing the biting fly attacks, relative to that from the traditional pesticide application (permethrin), but with an even lower cost in material use. This is the first successful trial using a push-pull strategy to management biting flies on cattle worldwide.
2. Broad applications of coconut fatty acid repellents against mosquitoes, ticks, and other insect pests. In addition to the strong repellency found from the coconut fatty acids and their major ingredient compounds against stable flies, ARS scientists in Lincoln, Nebraska, have further discovered their broad applications against other blood-sucking insect pests. Together with several external partners, we developed and tested the repellent effectiveness from coconut fatty acid impregnated fabrics for U.S. military, and lavender oil-based coconut fatty acid repellent lotion against mosquitoes and ticks that not only attack humans but also transmit many diseases. The long-lasting deterrence discovered from these fatty acids contained prototype products can provide over week-long deterrence against these blood-sucking insects. Prototype products have been developed with effectiveness equal or better than those of DEET-contained commercial products.
3. Compositions and methods for fruit fly oviposition deterrence. Spotted wing drosophila, tephritid fruit flies and Mediterranean fruit flies are serious pest of fruits and vegetables worldwide. Insecticides are currently the primary strategy for managing damage from these flies. Researchers at USDA-ARS in Lincoln, Nebraska, and collaborators at ARS Hilo, Hawaii, and industry partners have identified novel oviposition deterrents for these fruit flies. These compounds are generally regarded as safe and have excellent potential as a novel management tool to control fruit fly damage in susceptible crops through behavioral manipulation. This discovery has created some new environmental-friendly management tools for U.S. fruit producers battering against various invasive fruit fly pests.
Review Publications
Agnew, J., Gorzelski, A., Zhu, J.J., Romero, A. 2023. Coconut fatty acids exhibit strong repellency and week-long efficacy against several urban pest arthropods of the southwestern United States. Pest Management Science. https://doi.org/10.1002/ps.7531.
Roh, G., Kendra, P.E., Zhu, J.J., Roda, A., Loeb, G.M., Tay, J., Cha, D.H. 2023. Coconut oil derived five-component synthetic oviposition deterrent for oriental fruit fly, Bactrocera dorsalis. Pest Management Science. https://doi.org/10.1002/ps.7584.
Farooq, M., Qualls, W.A., Bangonan, L., Xue, R., Peper, S.T., Aryaprema, V.S., Benz, K., Zhu, J.J. 2022. Efficacy evaluation of medium-chain fatty acids as skin and spatial repellents against Aedes aegypti (Diptera:Culicidae) mosquitoes. Journal of Medical Entomology. 60(2):333-338. https://doi.org/10.1093/jme/tjac184.
Lehmann, A., Brewer, G., Boxler, D.D., Zhu, J.J., Hanford, K., Taylor, D.B., Kenar, J.A., Cermak, S.C., Hogsette, Jr, J.A. 2023. A push-pull strategy to suppress stable fly (Diptera: Muscidae) attacks on pasture cattle using a coconut oil fatty acid repellent and attractant lures. Pest Management Science. 79(9):3050-3057. https://doi.org/10.1002/ps.7480.
