It’s still summer, so the flies are still here. In fact, their populations are growing in many animal production facilities, including cattle operations, according to a Kansas State University entomologist.
“For control, management and prevention of flies, it is important to know what fly species is causing the problem,” said Ludek Zurek, medical and veterinary entomologist with K-State Research and Extension.
Three fly species are major pests of cattle – horn flies, stable flies and house flies. Zurek provided these basics producers should know about all three:
Male and female horn flies bite and feed on the blood of animals. They are about half the size of house flies. Horn flies usually gather on the shoulders, back and sides of animals. On hot days they move to the underside of the belly.
Unlike other flies, they stay on the animal and leave only when disturbed or when females lay eggs in fresh animal feces.
The ways to control horn flies, include ear tags, sprays, pour-ons, dust sprays and back rubbers. There are several brands for producers to choose from.
“One ear tag per animal is good enough,” Zurek said. “But, not every animal needs to be tagged for horn fly control. Tagging every third animal with one tag will provide good control because horn flies move between animals and eventually will take blood from the tagged animal – which will kill the fly. Try rotating two years on organophosphate tags, one year on pyrethroid tags, two years on organophosphate tags, and so on.”
Male and female stable flies bite and feed on blood from animals and people. They leave black or dark red spots on surfaces where they rest.
“On cattle, bites most often occur on the legs,” Zurek said . “Cattle react to stable flies by bunching up and standing in water, which helps protect from bites, but reduces feeding and decreases weight gain.”
Larvae develop in manure mixed with soil, straw or hay, as well as in decaying spilled grain and fermenting grass clippings. Development of the stable fly from egg to adult takes three to four weeks.
Currently, there are no effective control methods for stable flies on pastured cattle, Zurek said.
“Research indicates that stable flies in pastures develop in sites where round hay bales are fed to cattle during the winter,” Zurek said. “Steps should be taken to minimize hay waste and accumulation or to spread the wasted hay into thin layers.”
Despite their name, house flies can be found outdoors as well as in. House flies do not bite, but can transmit food-borne and animal pathogens.
House flies generate brown or yellow spots on walls and other surfaces where they rest. They are common from spring to late fall.
House fly larvae can develop in any decaying organic substrate, including animal manure, compost and garbage. Under ideal conditions, house flies’ development from egg to adult takes only eight days.
“The key to controlling house flies is a good sanitation program that includes maintaining good drainage, cleaning around feed bunks, under fences and gates, and around water systems,” Zurek said.
There are also baits and residual sprays that can help control house flies, Zurek said. Baits are available in granular form or a form that can be dissolved in water for paint-on application. Sprays are applied where the flies rest.