Submitted to: Journal of Vector Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 15, 2005
Publication Date: December 1, 2005
Citation: Geden, C.J. 2005. Methods for monitoring outdoor populations of house flies, musca domestica l. (diptera: muscidae). Journal of Vector Ecology. 30(2):244-250. Interpretive Summary: House flies have long been known to transmit a variety of diseases to humans and animals. Recent concerns about food-borne human illnesses have led to renewed interest in the role of flies in spreading disease-causing organisms. When fly production and dispersal from animal agricultural facilities exceeds levels acceptable to the public, public health workers and entomologists are often consulted to develop fly management programs. A critical element of such programs is the use of monitoring methods to document their effectiveness. At present there is no standard method for measuring fly populations outdoors. In this study, conducted by a scientist at USDA's Center for Medical, Veterinary and Agricultural Entomology in Gainesville (Florida), several different methods for monitoring flies in outdoor settings were compared. Testing was done in the field on Florida dairy farms with high fly populations. Sticky traps were effective, but quickly became saturated with flies when populations were high. Baited jug traps were also effective, but the bait had an objectionable odor and declined in effectiveness in hot weather. A new sampling method was developed in which dry baited strips were suspended beneath plywood shelters and placed over a pan to collect flies that fed on the bait and died. These traps collected more flies than any of the other techniques, were easy to service, and involved no sticky material or malodorous liquid baits. The results provide public health workers with an effective and simple way of monitoring flies.
Technical Abstract: Relative collections of house flies were compared on two Florida dairy farms using several monitoring methods: sticky cylinders, baited jug traps (Farnam Terminator and Victor Fly Magnet), and bait strips (Wellmark QuikStrike). Bait strips were placed over collecting pans and under 61 cm square plywood roofs to protect the toxicant from sunlight ("sheltered QuikStrike traps"). Sticky cylinders collected the fewest flies (515-679 flies/trap/day) and sheltered QuikStrike traps the most (5,659-8,814 flies/trap/day). The two baited jugs collected a similar and intermediate number of flies, with collections highest during the first 2 days after placement (2,920-5,462 flies/trap/day). Jug trap collections were low after 4 days of use in the field, apparently due to deterioration in the attractiveness of the bait over time. Jug traps collected mostly females whereas sticky cylinders and sheltered QuikStrike traps collected mostly males. Exposure of jug trap bait (Farnam) to fly cadavers for three days did not increase attractiveness of the bait. Combinations of the Farnam and Victor attractants were more attractive than either attractant alone and 25-43% more attractive than expected based on the sum of collections in the single-attractant traps. A 25% solution of farm-grade blackstrap molasses was as effective as either of the twp proprietary baits tested.