CEPS/Veterinary Extension
2938 Vet. Med. Basic Sciences Bldg.
2001 S. Lincoln Ave.
Urbana, Illinois 61802
Phone: 217/333-2907

By Joseph Hahn
Information Specialist
University of Illinois
College of Veterinary Medicine

Integrated pest management (IPM), an environmentally friendly technique developed in the 1960s to control destructive insects in crops and gardens, is now being applied to some nasty external parasites of horses. IPM has three main components: cultural control (good sanitation practices), biological control, and chemical application.

"The most important goal in IPM is to decrease the amount of chemicals (insecticides) needed to control pests, such as stable flies and houseflies," says Dr. Doug Keen, veterinarian and parasitologist at the University of Illinois College of Veterinary Medicine at Urbana. "Of the three components of IPM, cultural is often the one used most effectively by horse owners."

For example, one cultural control technique is to eliminate the places where larvae of the pesky flies develop. To do this, Dr. Keen recommends cleaning thoroughly--getting rid of manure, wetted bedding, spoiled/rotten food--every 10 to 14 days. Cleaning this often will help break the reproduction cycle of these flies.

"Biological control involves the use of non-traditional practices to control pests," says Dr. Keen. "Parasitoid wasps can be used to control stable flies and houseflies."

Wasps of the Pteromalidae family are released in overwhelming numbers. Approximately 2 mm in size and unable to sting mammals, these wasps lay their eggs in the pupal (cocoon) stage of developing flies. Instead of a fly, a new wasp emerges from the pupa and lays eggs in up to 30 other pupae.

"The two important factors in using wasps to control flies are getting the correct species of wasp and proper planning," says Dr. Keen. "There are many species of wasps commercially available, and different species of wasps work on different species of flies. Proper planning also allows wasp numbers to be high when pupae numbers are high."

The final aspect of IPM is chemical control. This means using traditional insecticides to control pests. With IPM, less insecticides are used, which translates to a lower cost, less insecticide resistance by the flies, and less environmental pollution.

Research is still being conducted on IPM and current techniques, but the advantages are numerous:

• IPM is more environmentally sound than conventional insecticide techniques.
• IPM has easy-to-follow principles, most importantly, good sanitation.
• Because IPM minimizes the use of insecticides, it is often a more economical approach to pest control.
• If you would like further information, contact your local equine veterinarian.