Make comfort and pounds count with good fly control
By Mike Catangui, Ph. D
Warm weather is indicative of flies and the need for good fly control for both cattle and worker comfort, animal productivity, and disease control. MWI’s entomologist, Dr. Mike Catangui, offers advice on how to control different species of flies that plague pastured and confined cattle in warmer months, with populations often spiking in late summer, early fall.
Face flies (Musca autumnalis)
Fly pests of pastured cattle
Face flies feed on the secretions of the eyes and muzzle of pastured cattle. Face flies need to be controlled in pastured cattle to minimize bacterial transmission that causes pinkeye disease in the herd, says Catangui.
Behavior: Non-blood-sucking. They only feed on serum/ blood secretions from pre-existing wounds. They are indistinguishable from house flies but, after landing, face flies move immediately to the host animal’s eyes. Their mouthparts have sharp teeth used to scrape conjunctival tissue; this irritation increases tear production and weeping on cattle cheeks.
Cattle reaction: Flapping ears and shaking of head from side to side.
Economic threshold: About 10 flies per animal
Control tips from Catangui:
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Insecticidal cattle ear tags and insecticides delivered through dusters and backrubbers have effectively been used to control face flies in pastured cattle
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Water-based and oil-based on-animal sprays are also effective in controlling face flies in pastured cattle using appropriate spray equipment
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Feedthrough larvicides are also available to prevent face flies from breeding in cattle manure in pastures
Horn flies (Haematobia irritans)
Fly pests of pastured cattle
Horn flies congregate on the shoulders, back, sides, and abdomen of pastured cattle. These flies need to be controlled to optimize the weaning weights of calves, milk production of cows, and the weight gains of growing cattle, says Catangui.
Behavior: Blood feeders. Each female horn fly feeds up to 40 times per day, biting the animal at least that many times. As temperatures rise, horn flies move down the sides of cattle. Horn flies spend nearly all of their time on host animals, making control easier with insecticide applications.
Cattle reaction: Switching tails over backs (rumps), throwing heads over shoulders, and bunching.
Economic threshold: About 200 flies per animal or 100 per side
Control tips from Catangui:
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Insecticidal pour-ons and capsules, insecticidal cattle ear tags, and insecticides delivered through dusters and backrubbers have been effectively used to control horn flies in pastured cattle
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Water-based and oil-based on-animal sprays are also effective in controlling horn flies on pastured cattle using appropriate spray equipment
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Feedthrough larvicides are also available to prevent horn flies from breeding in cattle manure in pastures
Stable flies (Stomoxys calcitrans)
Fly pests of pastured cattle, dairy calves, heifers, milking cows, and cattle in feedlots
Stable flies feed on blood from the legs of cattle; manage stable flies with this very basic biological information in mind, recommends Catangui.
Behavior: Blood feeders that prefer to bite the legs and bellies of cattle. They possess a large mouthpart and inflict a painful bite while feeding once or twice a day.
Cattle reaction: Foot stomping, tail switching, bunching, and spending lengths of time in water for protection from fly.
Economic threshold: About 4–12 flies per animal
Control tips from Catangui:
Stable flies need to be controlled when the cattle herd exhibits bunching behavior, excessive leg stomping, leg muscle twitching, and tail switching.
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Spraying cattle with water-based or oil-based on animal sprays is the preferred and most effective means of controlling stable flies in confined (dairy farms and feedlots) and pastured (cow-calf) cattle.
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Make sure to use the right equipment when spraying for stable flies; the spray needs to reach the legs of cattle where the stable flies bite.
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Effective spray products containing natural pyrethrins or synthetic active ingredients are available for stable fly control on dairy, feedlot, and pastured cattle. Larvicides controlling stable fly larvae in breeding sites are also available.
House flies (Musca domestica)
Fly pests of dairy calves, heifers, milking cows, and cattle in feedlots
House flies can multiply to very high numbers in feedlots and dairy farms They are known carriers of microorganisms that can cause diseases in cattle and humans.
Behavior: Non-blood-sucking. They only feed on serum/ blood secretions from pre-existing wounds. They are indistinguishable from face flies but, after landing on a host’s face, house flies move to the nostrils and mouth.
Cattle reaction: No harmful effects on cattle, so little defensive behavior.
Control tips from Catangui:
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House fly baits can be used to lure adult house flies away from calf hutches, feed bunks, feed storage areas, and animal housing. House fly baits are available as solid scatter baits, sprayable baits, bait strips, and pressurized ready-to-use sprays.
- To quickly reduce adult house fly numbers over large areas, the animals and their immediate surroundings can be sprayed with on-animal sprays using appropriate spray equipment.
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Products containing natural pyrethrins are effective in dairy farms and feedlots where house flies have developed widespread resistance to synthetic insecticides.
- Larvicides formulated as sprays, granules, and animal feedthroughs are available to control house fly larvae in breeding sites; empty-barn residual sprays can be used in empty buildings away from the animals.
