Biological Control of the Horn Fly, Haematobia irritans L., in Hawai'i (Diptera: Muscidae)

The effort to control the horn fly, Haematobia irritant (L.), is one of the longest (1898 to 1982) and most extensive attempts at biological control in Hawai'i.By the late 1950s, 45 species of parasites, predators, and competitors (dung beetles) had been introduced, 20 of which became established.Horn fly control was considered satisfacto ry by some ranchers at lower elevations and drier sites, but unsatisfactory at higher and wetter locations.In a new program from 1973 to 1982, 9 additional species of South African dung beetles were introduced by way of Australia.All but 1 species were found established in 1989.The distribution and relative abundance of agents found in a 1985 survey is presented.Haematobia irritans (L.) is a small muscid fly, native to (he Mediterranean area, that is about half as large as the common house fly.It pierces the skin of cattle and, occasion ally, horses, sheep, humans, and other animals to suck blood (Herms 1950).When flies are numerous, their painful bites interfere with feeding and resting of cattle, resulting in weight loss and reduced milk production.The flies are found commonly on the shoulders, but sometimes are observed around the base of the horns in a dark band, giving the fly its common name.Female flies dart down to deposit eggs on fresh cattle dung, usually when the dung pads are only minutes old and still warm.Eggs hatch in a day or two, and larvae develop in the dung pads.