Use of a highly sensitive immunomarking system to characterize face fly (Diptera: Muscidae) dispersal from cow pats.

We tested an immunomarking system that used egg white as marker and enzyme-linked immunosorbent assay as a detection assay to characterize face fly (Musca autumnalis DeGeer) dispersal from cow pats in a pastured beef cattle operation. In microcage assays, adult flies acquired marker after contact with cow pats that were treated with marker and field aged up to 11 d. In arena assays on sprayed full-size cow pats, 77% of eclosed face flies acquired the marker. In a field-marking study, four applications of egg white marker were applied on freshly deposited cow pats over a summer at two peripheral paddocks to a main grazing pasture of ≍50 head of beef cattle. Of the 663 face flies captured, 108 were positive for the egg white marker (16.3%). Of the marked flies, ≍ twofold more male than female flies were captured. Sex-specific dispersal distances were roughly equal up to 450 m, with 11% of female flies dispersing >450 m. Dispersal capability of face flies is discussed in relation to efficacy of rotational grazing and other IPM strategies.

Evaluation of sunlight-exposed pyrethroid-treated netting for the control of face fly and housefly (Diptera: Muscidae).

BACKGROUND: Face flies, Musca autumnalis De Geer (Diptera: Muscidae), and houseflies, Musca domestica L. (Diptera: Muscidae), have a significant impact on livestock and dairy production throughout North America. Pyrethroid insecticide efficacy can be affected by exposure to direct sunlight, and the rate of photodegradation is substrate and formulation dependent. Insecticide-treated netting (ITN) is finding new applications in crop and livestock production systems. A baseline study using long-duration no-choice assays has been carried out to gauge the effectiveness of ITN treated with ß-cyfluthrin, λ-cyhalothrin and bifenthrin on face flies and houseflies. RESULTS: After 12 weeks in direct sunlight, ITN treated with ß-cyfluthrin was still highly insecticidal to face flies and houseflies, producing 100% mortality in petri dish assays. However, sunlight reduced the insecticidal activity of λ-cyhalothrin, with 3% of face flies and 50% of houseflies surviving after exposure to ITN that had been deployed for 10 weeks. Insecticidal activity was greatly reduced on bifenthrin-treated netting, with 20% of face flies and 50% of houseflies surviving in assays with netting deployed for only 3 weeks. CONCLUSION: With careful choice of the pyrethroid applied, treated netting could be an important component of livestock integrated pest management programs focused on sustainable practices.