Cattle Fly Control: Horn Fly Biology

1/27/2010 3:33:45 PM

The horn fly was accidentally introduced into the U.S. from southern France prior to 1886. This small fly (approximately 1/8 inch long) is about half the size of a house fly and is known for spending most of its time on the back, head and shoulders of its host. During very hot or rainy weather, horn flies may move to the belly. In addition to being smaller than the house fly, horn flies can be differentiated by their piercing mouthparts that resemble a beak. Horn flies only leave the animal to lay eggs on fresh cattle manure, less than 10 minutes old. Both sexes feed on cattle by taking 20 to 40 blood meals per day. Populations of up to 10,000per animal have been documented but normally do not reach this extreme. Development from egg to adult occurs in as little as 912

days. Eggs hatch and larvae develop within the manure . Mature larvae migrate to the lower portion of the manure pat or in the soil to pupate. Adults emerge after about 5 or 6 days. Horn flies mate and seek a host to begin blood feeding a couple of days after emergence. An adult female may begin laying eggs three days after emergence and may lay up to 400 eggs during her lifetime. With such a short life cycle, many generations per year are possible, making it a very good candidate to develop insecticide tolerance, especially in southern areas.

Horn flies survive the winter as pupae in the soil. Adults emerge in mid March with populations peaking in late May or early June. Horn fly presence or absence is temperature dependent, while abundance is influenced by humidity and precipitation. Therefore, during the dry and hot months of summer, populations normally decrease. In September, as temperature decreases and humidity and rainfall increase, populations will peak again.

Source: Arkansas Ag Extension