Livestock News

Which Wasp To Use Against House Fly in Barns?

Parasitoid wasps that attack fly pupae can be effective in managing house flies and stable flies in dairy barns and poultry houses. There are many commerically available filth fly parasitoids, but which species is best? Two species, Muscidifurax raptorellus and M. raptor, were evaluated in New York for their ability to find hidden fly pupae and their rates of parasitism.

Both of the wasps killed more fly pupae on the surface of straw bedding than those that were buried 3/4 inch beneath the straw. Neither species found the buried pupae in a 24-hour period. Parasitism rates were equal for the two species.

M. raptorellus is considered the more promising biocontrol agent because it can lay 6-8 eggs in each fly pupa and thus build up its population more quickly than can M. raptor, which lays only one egg per pupa. However, cool temperatures may eliminate this advantage. M. raptorellus produced multiple progeny only when the temperature was above 65F. The next step in determining which wasp provides superior control is to compare the efficacy of mass releases of the two wasps on dairy farms.


New York State Integrated Pest Management Program Annual Report, 1998

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