Location: Mosquito and Fly Research2011 Annual Report
1a. Objectives (from AD-416)
1. Provide better tools for surveillance and risk assessment by: studying house fly feeding behavior, resource location, and nutrition under field conditions; developing more efficient stable fly attractants; studying specific behaviors of adults; and determining the risk of introduction of Stomoxys species other than calcitrans and prioritize the risk of other potentially invasive fly species, including traps that sample across the entire population of adults and produce results with quantifiable error terms. 2. Develop more efficient integrated pest management by determining weaknesses within fly life cycles and matching these weaknesses to appropriate chemical control methods; and by developing biologically-based and bio-rational control methods. 3. Conceive and test applications of behavior-altering methods (e.g., behavior altering devices, attractants, repellents) for practical use, including repellents for livestock. 4. Determine the role of flies in dissemination of priority food safety pathogens including the role of some of the less-studied species of flies.
1b. Approach (from AD-416)
Nutritional attractants of house flies will be identified and new chemical lures for stable fly traps will be developed. Trapping data will be used to determine the risk of introduction of exotic Stomoxys spp. at ports in the southeastern U.S. Virus-based baits from candidate strains will be developed to control house flies. Systems for production of Diapriid parasitoids will be ready for transfer to commercial insectaries. These parasitoids can be effective for management of immature stable flies and house flies. New stable fly repellents for use on livestock will be evaluated in laboratory and field trials. Behavior-altering chemicals/surface combinations to repel and/or kill house flies will be evaluated in the laboratory with the aid of video monitoring and evaluation systems. An insecticide-based perimeter treatment method to provide protection against dispersing flies will be subjected to final field evaluations. The role of house fly in transmission of Salmonella enteriditis via contaminated poultry feed will be determined by exposing flies to contaminated feed and measuring their ability to transfer the pathogen to clean substrates.
3. Progress Report
All milestones for this research project have been fully or substantially met during the reporting period. House fly fecundity was found to be related to certain feedstuffs on dairy farms. For example, brewers’ grains and sorghum did not support fly egg development, calf feed supported partial development, and calf manure was as nutritious as the standard lab diet. So far, the blends of attractive chemicals for stable flies have not produced better results than the best attractant chemical by themselves. Testing will continue as will synthesis of some of the requisite chemicals. A major effort will be concentrated at Brunswick, Georgia, which will allow for a round trip by government vehicle in one day. Traps are ready for use and placement has been discussed. Monitoring is set to begin later in the summer. House flies fed the salivary gland hypertrophy virus (SGHV) were not becoming infected because the virus could not cross the peritrophic membrane that surrounded the virus in the gut lumen. However, by feeding the flies on chemical reducing agents, the gut became permeable and the flies became infected with the SGHV. A complete year of sampling in the southeastern United States has been completed and selected strains have been colonized in the insectary. Laboratory evaluation of ARS stock compounds is almost complete and testing will continue through the end of the year. Attractive surfaces for outdoor testing have been selected and will be ready for use during the winter stable fly season. Evaluation of candidate surfaces for house fly preference continues mainly because house flies will land on many surfaces. However, work will continue and candidate groups of attractive surfaces will be compared later in the summer. Research with insecticide-impregnated targets has shifted to insect growth regulator-treated targets because house flies have become resistant to most of the pesticides registered for use. Flies pick up the growth regulator, pyriproxyfen, and pass it into the environment through their eggs, where it kills the immature stages of the fly. This controls flies in areas where pesticides cannot reach, and limits pesticide usage. Research for the role of house flies in transmitting Salmonella enteritidis will begin in month 36 of the project.
1. House fly fecundity on different foods. ARS researchers at Gainesville, Florida, needed to know if the number of eggs produced by house flies on dairies is altered by available food sources. Some foods, like brewers’ grains and sorghum, did not support egg development at all whereas calf manure was as nutritious for the flies as the standard lab diet. The results may be useful in efforts to limit fly access to those foods that maximize their reproduction.
2. Salivary gland hypertrophy virus of house flies. Flies prevent becoming infected from ingested pathogens by surrounding their gut contents with a protective, impermeable membrane. ARS researchers at Gainesville, Florida, enabled the salivary gland hypertrophy virus (SGHV) to pass through the protective membrane by feeding flies on chemical reducing agents that disrupted the membrane. These flies then became more susceptible to a virus-laden food bait. Results may lead to new methods for infecting flies with SGHV and other biocontrol agents that must be administered orally.
3. Insecticide-treated targets and flies as autodissemination vehicles for pyriproxyfen. Agricultural Research Service researchers at Gainesville, Florida, developing visual targets for a house fly attract and kill system, have switched from pesticides, to which most flies are resistant, to the growth regulator pyriproxyfen, an agent that blocks the development of immature fly stages so no adults are produced. When flies visit pyriproxyfen –treated surfaces, they carry the material with them and will deposit it when they lay their eggs, thus affecting the immature stages of other flies. Results could lead to development of self-treating stations and greatly reduce pesticide use.
4. Size and presentation of insecticide-treated targets for stable fly management. Agricultural Research Service researchers at Gainesville, Florida, developing visual targets for stable fly management needed to know if target size and shape affect attraction. The smallest of three rectangular targets attracted the fewest flies, but the most flies per square inch of target. There were no adverse effects using flat or cylindrical targets or with the two contrasting target colors side-by-side, or spatially separated. Results will allow the use of a variety of target shapes and sizes tailored to the desired use. The visual targets are designed so stakeholders can easily prepare them for their use, and these results provide stakeholders with a number of target configurations and sizes that can be used to match their particular situation.
Pitzer, J.B., Kaufman, P.E., Geden, C.J., Hogsette, Jr, J.A. 2011. The Ability of selected Pupal Parasitoids (Hymenoptera: Pteromalidae) to Locate Stable Fly Hosts in a Soiled Equine Bedding Substrate. Environmental Entomology. 40(1):88-93.