Animal Facilities
Management of house flies in animal facilities is considerably more difficult than in urban locations. The continuous and substantial production of animal feces in these facilities can provide an abundance of resources for larval fly development if not managed carefully.
At animal facilities, house flies are best managed through manure sanitation to reduce larval development. Larvae are less mobile and restricted to their developmental habitat (primarily manure), which makes them easier targets for control. When sanitation alone cannot reduce fly numbers sufficiently, chemical or biological control options may also be utilized.
 

Cattle Facilities 
Elimination of larval development sites by regular manure removal is essential for reducing house fly abundance. It is particularly important to remove wet manure near watering stations, beneath fence lines, and adjacent to any structures within the pen where manure builds up and cannot be compacted by cattle as they move about their pen. Manure solids generated by screening effluent from flush-lane systems will also produce large numbers of flies if not properly handled. Removed or separated manure should be composted to generate fly lethal temperatures or spread in a thin layer (by harrowing) within the animal pen for rapid drying and to be compacted by animals. Composting manure piles or windrows will need to be turned following rain or other wetting event to prevent fly development in the wetted and cool outer portion of the pile or windrow. Removal of manure buildup within animal pens and at manure separators should occur at least 1-2 times per week during the hotter summer months to prevent immature flies in the manure from completing their development.

 

Engineering controls to ensure proper drainage of drylot pens and flush lanes are also critical to reducing house fly production. Animal pens should be graded to allow rainwater to drain quickly for more rapid drying of manure within the pen. Drainage channels should be constructed outside drylot pens so that cattle cannot degrade the integrity of these drainage channels to cause pooling of water within the pen. Any water pooling within the pen will result in house fly production.
 

Poultry Facilities 
Manure management in poultry facilities varies with facility design, but removal and rapid drying of wet manure and wet feed is the key to successful fly management in all designs. In high-rise egg-layer operations, manure is often allowed to build up beneath rows of hen cages forming a ridge of manure the length of the cage row (drying and coning method). Fresh, wet feces deposited on top of this ridge are expected to dry quickly reducing the opportunity for fly development. However, if the drying rate of the feces is reduced due to limited air movement, overstocking of birds, high humidity, or sick birds depositing particularly wet feces, then this method will be easily compromised and house fly production can be significant. Weekly removal of bird feces (frequent clean out) followed by composting of the feces or by spreading the feces in a very thin layer to dry quickly is often recommended when fly feces cannot be dried sufficiently beneath hen cages.
 

Biological control 
The use of natural enemies, such as predators or pathogens, to reduce pest numbers is called biological control. Under natural conditions, there are several species of parasitoid wasps that lay their eggs on fly pupae, killing the pupae as the parasitoid larvae develop. Some of these parasitoid wasps may be purchased from commercial breeders and released at locations on the animal facility to augment natural populations of these parasitoids. Several species of beetles and mites that prey on fly eggs and larvae are also active under natural conditions. To promote the management of house flies by natural populations of parasitoids and predators, application of broad-spectrum insecticides to manure, where these biological control agents are active, should be avoided. Entomopathogenic fungi that kill flies are also common on animal facilities. However, the efficacy of these fungi depends on temperature and humidity, and the probability of flies being infected with these fungi is low during the hotter summer months when control of flies is most desired. This seasonal variation leaves entomopathogens as an unreliable control method.
 

Chemical control 
Most chemical control methods target adult fly populations and should be used when non-chemical methods targeting larval development have failed. Perhaps the mostly commonly used chemical control products are granular baits which combine fly attractants, such as the fly pheromone (Z)-9-tricosene, with an insecticide. Granular baits can be easily and quickly spread on the ground in outdoor areas inaccessible to animals, or they can be placed into fixed-site bait stations. Granular fly baits are most effective when placed near areas where fly activity is already high. Liquid insecticides can be applied as a spray to structures on which flies are noted to rest or can be applied as a mist or fog to achieve control in an enclosed area. Some insecticides targeting the immature fly stages can be mixed with animal feed and applied as a feed-through. Animals consume the feed, and insecticide is excreted with the animal feces preventing fly larvae from developing in the manure. House flies will quickly develop resistance to insecticides used continuously. To manage insecticide resistance, use insecticides only when needed for immediate control of adult flies and vary the chemical class (IRAC code) of insecticide used on a seasonal or annual basis. For your safety and the animals' safety, please observe the label instructions for proper application methods.