Location: Mosquito and Fly Research2011 Annual Report
1a. Objectives (from AD-416)
1. Discover and evaluate new toxicants and biological control agents for control of biting Nematocera. 2. Develop new application methods for pesticides to biting Nematocera that minimize environmental exposure and that optimize lethal or repellent effect, including presentation on clothing, aerosol application in or outdoors, residual application, disinsection of aircraft, and delivery of spatially repellent compounds. 3. Conceive and test new methods of managing vector and pest populations through the use of behavior-altering chemicals, including repellents, attractants, and inhibitors. 4. Examine the parameters of behavioral bioassay methods that influence practical comparisons of personal protection products, with a view to determining those elements of commercial testing that influence reliability of results. 5. Determine chemical and other cues associated with regulation and orientation of specific behaviors by Aedes albopictus, Culex pipiens group species/hybrids, and other biting arthropods that can be applied to the solution of operational surveillance and control problems. 6. Discover and characterize environmental predictors of the distribution of mosquitoes in order to assess the risk of invasive species and pathogen transmission. Apply to the development of methods and techniques to accurately assess mosquito population density, to deploy vector surveillance systems, and to detect exotic invasive species.
1b. Approach (from AD-416)
1. High throughput bioassays will be used to screen candidate toxicants from libraries of synthetic compounds and natural products. Bacterial toxins, baculoviruses, and biorationals will be evaluated in new formulations in standard assays. Molecular methods (RNAi and dsRNA) will be used to identify targets for control and resistance management. Improved formulation and delivery of dsRNA will be developed to penetrate the mosquito cuticle. 2. Factors affecting measurement of bite protection by permethrin-treated clothing will be examined. Alternative repellents applied to military uniforms and improved binding of repellents to fabric will be researched, followed by laboratory validation of factory-treated fabric and semi-field studies. Aerosol applications of control compounds, using different formulations, equipment, techniques, and strategies will be explored. Existing and novel chemical compounds, formulations, equipment, impregnated materials, application techniques, and strategies for barrier applications will be evaluated under laboratory, semi-field and field conditions. Factors needed to achieve optimal control will be identified. Air curtains will be designed and evaluated in simulated aircraft fuselages. 3. Comparison of pathogen-infected and uninfected mosquito responses to behavior-altering chemicals will be examined. Baited commercial traps will be used as surrogates for human and livestock hosts. The manner in which compounds affect host-seeking behavior will be quantified. Catches in control and attractant-baited traps located near devices releasing spatial repellents or inhibitors will be compared. 4. The effect of mosquito fatigue on repellent protection time will be evaluated with female Aedes aegypti and a study comparing methods for measuring repellent efficacy will be conducted. Laboratory results of repellent efficacy will be compared to products tested in the semi-field environment. 5. Factors that result in positive resting site selection responses by adult mosquitoes, volatile chemical cues associated with mate location, and cues used for location and utilization of sugar and nectar sources will be determined. Plant-derived compounds that attract mosquitoes will be evaluated in the field. Factors that influence host-finding behavior based on host odors and olfactory cues will be used to enhance traps. Novel strategies for mosquito surveillance that utilize oviposition site cues will be devised. New chemical attractants will be identified and evaluated in the field using behavioral and chemical analyses. The response to toxicant exposure on arthropod behavior will be evaluated to improve toxicant impact. 6. Methods and techniques to assess mosquito population density will be developed. Environmental predictors of mosquito distribution will be characterized to provide improved strategies for assessment of mosquito populations. Discover ecologic and climatic factors to assess population densities of vector mosquitoes in the US and, using Rift Valley fever, evaluate the risk of exotic species and disease introduction into the U.S.
3. Progress Report
Biting Nematocera transmit pathogens that cause diseases such as West Nile virus, dengue, malaria, leishmaniasis and filariasis to humans and animals in urban, suburban, and rural areas and in agricultural, recreational, and military environments. This research project is focused on improving the control of biting Nematocera through a better understanding of their biology and the development of novel products, technologies, and control strategies. Research with gene silencing technology has led to the development of RNA interference (RNAi) strategies through the use of Highly Specific Pest Control (Hi-SPec) substances in combination with attractant sugar sources. This type of trapping system can be used as part of an integrated pest management control strategy to reduce disease risk to humans and animals. Results from larvicidal and adult screening with insecticides resulted in promising new compounds that may become alternative insecticides for mosquito and fly control. Current and new U.S. Army uniform materials were evaluated for their ability to prevent mosquito bites. The protection of U.S. military personnel from diseases transmitted by insect bites is critical to the success of our military missions. The bite protection of Fire-Resistant Army Combat Uniforms (FRACUs) treated with permethrin by factory-treatment was completed. The results of the studies with uniforms were used by the U.S. Army to award contracts to suppliers of these uniforms. The data generated for U.S. Marine Corps was submitted to the U.S. EPA for label registration of permethrin-treated uniforms. Historically, a control strategy for use against mosquitoes that transmit malaria in Africa has been through the treatment of the inside walls of dwellings with Indoor Residual Sprays (IRS). As an alternative to IRS, Durable Residual Wall Linings (DL) have been evaluated and found to produce 100% kill of mosquitoes, 8 months after initial usage. Ultra-Low Volume (ULV) tests of a sumithrin/prallethrin combination insecticide was found to be superior to other ULV insecticides for the control of mosquitoes and flies in Sub-Saharan Africa. Additionally, camouflage netting treated with bifenthrin significantly decreased mosquito and fly populations in areas where the netting was deployed. Laboratory tests indicated that the treated netting was still effective 18 months after the initial application. Novel spatial repellent appliqués that contained either nepetalactone or rosemary oil where shown to be effective at suppressing the ability of mosquitoes to find attractive odors.
Xue, R., Muller, G.C., Kline, D.L., Barnard, D.R. 2011. Effect of application rate and persistence of boric acid sugar baits applied to plants control of Aedes albopictus. Journal of the American Mosquito Control Association. 27(1):56-60.