Location: Mosquito and Fly Research2013 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:
Color and reflectance seem to be more important aspects of attraction for stable flies than chemicals. Results from monitoring of potential invasive species are difficult to evaluate because of low or nonexistent populations. A mathematical model of Salivary gland hypertrophy virus (SGHV) epizootiology indicated that male-male aggression plays a role in virus transmission; laboratory assays validated this hypothesis. A third year of collecting in Nebraska and the southeastern U.S. has been completed, selected parasitoid strains have been colonized in the insectary, and bioassays have begun with Spalangia drosophilae. Competition experiments with two species of Muscidifurax demonstrated that the timing of parasitization events is more important than the aggressive nature of the parasitoid immature in determining the victor. An “improved sentinel” method was further tested that allows highly efficient collection of large numbers of parasitoids from targeted sites. Additional collecting was done on beef cattle facilities in Nebraska in 2013; more than 200,000 fly pupae were collected and are being held for parasitoid emergence. Field evaluations of in-house and commercial attractant materials have been very positive. Studies are being conducted in 2 states in the U.S. and in several African countries. Surfaces which reflect light in the ranges which are attractive to stable flies can also be attractive to house flies. Coating these surfaces with adhesives would be preferable to using pesticides because of wide-spread pesticide resistance in house fly populations. 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 (PPF), and pass it into the environment along with their eggs, where it kills the immature stages of the fly. This controls flies in areas where pesticides cannot reach, and limits pesticide usage. Work continued this year with newly developed high-potency formulations. Studies with these formulations in large indoor cages were successful, as was the use of a PPF bait that targets adult flies. Research on the role of house flies in transmitting Salmonella enteritidis was halted by the retirement of the poultry science collaborator; a replacement collaborator has not been found.
1. Salivary gland hypertrophy virus (SGHV) of house flies. For several years ARS researchers at Gainesville, FL have attempted to infect flies with SGHV using baits but were unsuccessful. Recently we have found that surface contamination may be a more common route of infection, and that even small amounts of cuticular damage to the fly can provide routes of infection without ingesting the virus. A mathematical model of virus epizootiology was developed that suggested that the aggressiveness of male flies during courtship could provide an additional avenue of infection. This hypothesis was confirmed experimentally, and the results could lead to sprayable formulations of the virus to treat fly resting and aggregation sites.
2. Color and contrast of insecticide-treated targets for stable fly management. ARS researchers at Gainesville, Florida, developing visual targets for stable fly management, needed to know if targets of a single color can influence the captures on sticky traps placed nearby. Capture rates of stable flies on sticky traps were increased significantly by the placement of black cloth targets within 15-18 inches of the traps. Results support the use of targets-trap combinations to increase numbers of flies attracted by either device alone.
3. Attractive surfaces for stable flies and house flies. Sticky wraps made from thin packing foam were developed commercially to use on a particular stable fly trap. ARS researchers at Gainesville, FL, found these wraps to be highly attractive to stable flies when wrapped around objects other than the intended traps. Besides significantly increasing the numbers of flies captured on other fly traps, the packing foam wraps also captured flies when wrapped around cylindrical objects like propane tanks and barrels which are not intended to attract flies. Because these wraps will attract flies to objects that are not actually traps, this will allow the wraps to be used in a variety of ways to help monitor and manage fly populations.
Kneeland, K.M., Skoda, S.R., Hogsette, Jr, J.A., Li, A.Y., Molina-Ochoa, J., Lohmeyer, K.H., Foster, J.E. 2012. A century and a half of research on the stable fly, Stomoxys calcitrans (L.) (Diptera: Muscidae), 1862-2011: An annotated bibliography. Agricultural Research Service Publication. 173:1-163.