Fly parasites are tiny wasps that attack fly pupae. If they weren't common in nature, all our garbage would be covered in thick swarms of flies. There are a number of different species and each one performs differently in different situations.  Spalangia are found in hot, arid conditions because they do a better job of burrowing through dry and crusty surfaces. They are also prized because they attack stable fly pupae as well as housefly pupae.

Fly Parasite Release Program

From Herbs to Ribbons

Feeding grain and baled hay to animals is more likely to create fly breeding sites, especially in spilled grain and stacks of old damp hay near watering troughs. Good manure and feed clean-up are basic, combined on many dairies with sticky ribbons and baited jug traps including our large metal Sagebrush traps. Our thin, low-profile 1,000 foot ribbon is conveniently deployed from its reel to a take-up reel with a minimum of messy bulk to dispose of. 

Herbal fly repellant like Ecto-Phyte from Agri-Dynamics can be sprayed on cows. Essential oils form an aromatic vapor shield that repels flies, immobilizes parasites of animals and birds, and can kill insects on contact. Herbal repellent helps suppress "hotspots" of flies breeding in calf bedding. More below in article about Organic Dairy Conference.

Fly Control Catalog webpage