Flies Impacting Livestock, Poultry and Food Safety

NON-TECHNICAL SUMMARY: Muscoid flies are among the most important pests in livestock and poultry production systems. Two species in particular, house fly (Musca domestica) and stable fly (Stomoxys calcitrans), are responsible for damage and control costs in excess of a billion dollars per year in the United States. In addition to the direct damage these flies inflict upon livestock, their presence as a byproduct of confined livestock and poultry operations has been repeatedly cited as a common nuisance, especially when the flies enter the vicinity of human habitations and urban environments. In 2003, the Northeastern IPM Center Livestock and Field Crop working group created a list of prioritized needs (http://northeastipm.org/work livepriority.cfm). The group indicated that the "development of new integrated management of key pests of livestock and poultry in confined and pasture settings" was a top priority with specific reference to "stable fly breeding and migration in pasture systems" and "fly control methods for pasture and feedlot situations." Ten of the working group's 17 assessed needs and seven of the top 10 directly referred to muscoid flies. The 3 objectives of this proposal address 10 of the 17 needs. Packaging the information derived from this proposal for delivery to the stakeholders will address 2 additional priorities of this working group. Similarly, a 1994 Pest Control Survey in Texas indicated that house flies and stable flies were significant pests.

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APPROACH: 1) The seasonal dynamics of winter hay feeding sites will be evaluated by temporal and zonal sampling of feeding sites. Core samples will be collected and macrofauna isolated. Immature stable flies will be counted and characterized by instar. Other macrofauna will be quantified and cataloged. Emergence traps will be used to evaluate zonal and seasonal stable fly emergence. These data will be used to identify the zones and seasons of primary stable fly production in hay feeding circles so control strategies may be most effectively focused. Records of numbers of flies caught per trap per day in each of the 60 data sets (site-years) will be analyzed using mixed regression models to relate changes in catch rates to density and antecedent weather variables. 2) Cattle fecal swabs will be sampled every two weeks from each farm. Samples will be processed using thioglycollate enrichment broth supplemented with antibiotics under CO2 gas pack conditions to maximize Campylobacter growth. Cultures will be plated on Brucella blood agar and incubated at 42C. Campylobacter presumptive cultures will be tentatively identified and stored at -70C for subsequent PCR testing. 3) Chemicals which modify the pH of larval habitat such as lime, sulfur and citric acid and biological agents such as entomopathogenic nematodes and pathogens will be bioassayed in laboratory experiments to determine their effects on stable fly larvae. Compounds which effectively reduce larval survival in the laboratory will be tested in 1 meter2 plots in natural habitats. Plots will be delineated by frames driven into the media. Emergence traps will be used to evaluate control levels. Further details are in the proposal outline.