Entomologists are quite interested in using biological control in poultry houses. It is important to purchase beneficials climatically adapted to the region where releases are made. IPM Laboratories, Main Street, Locke, NY 13092-0300, Telephone: 315-497-2063, Fax: 315-497- 3129 is one of the commercial companies currently selling fly parasites tailored to the northeast climates, such as Ohio, for fly control.
These fly parasites are the naturally occurring enemies of manure-breeding flies. Flies are destroyed in the pupa stages. These parasites are very tiny wasps, Muscidifurax zaraptor, about the size of the head of a house fly (1/16 to 1/8 inch) which live in the manure, feeding on fly pupa. Adult female parasites lay an egg on the fly pupa within the puparium. Then the developing parasite larva consumes the pupa and emerges as an adult parasite. These fly parasites are specific to flies and do not attack anything else. They are biteless and stingless to humans and go unnoticed. They self-propagate in the process of controlling pest flies. However, due to low parasitism levels, mass releases are needed. Also, each wasp lays less eggs than each fly over the same time period, making it necessary to start with an initial wasp release with weekly supplemental releases following. Releases occur before and during the fly season. Chemical sprays must be discontinued in areas of the poultry house where these wasps are used. Never treat the entire manure surface with insecticides, with the exception of cyromazine (Larvadex), otherwise, both beneficial insects as well as pest flies will be killed. A strict sanitation program is required under fly parasite releases involving manure management, water management, weed mowing, etc. Keep manure dry, since wet manure promotes fly pest breeding and inhibits beneficial insect breeding. Also, when the poultry house is cleaned out, leave areas of old dry manure to provide a reservoir of beneficials to repopulate the house as new flies occur.
The use of fly parasites for biological control in Ohio would reduce chemical residues to humans, birds, eggs and the environment. However, to date, claims that wasps will provide long-term fly control have not always been backed up by scientific research results. Remember to manage the habitat for biological control by keeping the manure dry. Remove manure only during the fly-free time of the year and eliminate insecticide sprays in the manure pits. Undisturbed poultry manure accumulations over long periods of time will support large populations of native fly parasites (wasps and mites) and fly predators (beetles). Be sure to encourage native strains of beneficials already present in the dry manure to populate.
According to a Cornell and Penn State Cooperative Extension Publication, titled "Pest Management Recommendations for Poultry," other beneficials in poultry manure include mites and beetles. Both are major predators in caged-layer operations. The macrochelid mite Macrocheles muscaedomesticae, is reddish-brown, less than 1/16 inch long and feeds on both house fly eggs and first-instar larvae. These mites found on the outside layer of manure can consume up to 20 house fly eggs per day. Another mite is the uropodid mite, Fuscuropoda vegetans, which feeds only on first-instar house fly larvae deeper in the manure.
A hister beetle, Carcinops pumilio, is black, about 1/8 inch long and feeds on house fly eggs and first-instar larvae. This effective beetle predator, common in both broiler and layer houses, can consume 13 to 24 house fly eggs per day. Both adult and immature hister beetles live in the surface layers of manure. Also, another hister beetle, Gnathoncus nanus, is present at lower numbers on northeast poultry farms.