Livestock News

Nematodes as Potential Biocontrol Agents for House Flies

House flies are an important nuisance pest that must be managed in all livestock production systems. Nematodes have shown some potential as a biological control agent of the maggots of these flies.

In one experiment, the nematode Heterorhabditis bacteriophora (which was more effective than steinernematid nematodes in preliminary studies) was evaluated under barn conditions as a control agent for fly maggots in chicken manure. Manure in both a treated and control barn was about inch deep and covered about 80% of the floor area. Nematodes were applied over the manure surface with a pesticide sprayer at a rate of 500,000/yd2. Two weeks after the nematode treatment fly populations (assessed by counting fly specks deposited on white cards pinned up in the barn) were increasing much more rapidly in the control barn than in the treated barn. The fly population in the treated barn leveled off at about 20% of that in the control barn, and continued to drop in the three months after treatment, although no nematode-killed maggots were found after 10 weeks.

In another study, the basic biology of the recently described Paraiotonchium muscadomesticae, isolated from house flies in Brazil in the late 1970's, was investigated. Nematodes infect flies in the egg or larval stage. They don't always kill the maggots, but invade and damage the ovaries of surviving female flies. Heavily infested flies produce no eggs and live only half as long as uninfected flies. This nematode has considerable promise as a classical biological control agent for house flies. Infected flies can be produced in large quantities and could be released as 7-9-day-old infected flies on livestock and poultry farms. Much additional research is needed, however, before it can be released outside its present known home range in Brazil.

Sources:

Belton, P., T. A. Rutherford, D. B. Trotter, and J. M. Webster. 1987. Heterorhabditis heliothidis: A potential biological control agent of house flies in caged-layer poultry barns. J. Nematol. 19(2): 263-266.

Geden, C. 1997. Evaluation of Paraiotonchium muscadomesticae, a potential biological control agent of the housefly. Biol. Control 10: 42-47.


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