Haematobia irritans exigua: Buffalo fly

General Description: Similar to ho flies. This fly is a primary pest of cattle and water buffalo but occasionally feeds on horses, sheep and wildlife.

Life Cycle: The life cycle may take as little as 7 – 12 days depending on weather conditions. However, under cool weather conditions this may be prolonged to several weeks. Eggs hatch in 15 – 24 hours under favourable conditions (25¼ to 35¼). Larva burrows into dung, and under optimal conditions of moisture and temperature larval growth is completed in 4 – 5 days. Pupp takes place in or under the dung pad and adults in 3 to 5 days under these conditions.

Location: The fly is permanent parasite and rarely leaves the host other than to lay eggs in freshly passed faeces. When disturbed, flies rise off the host in swarms and then settle again.

Geographical Distribution: Northern Australia and New Guinea. Also parts of southern, south eastern and eastern Asia.

Significance: Flies cause a severe annoyance and irritation to animals thus interfering with grazing patterns. In addition, infested animals suffer from blood loss.

Effect on Host: Infested animals often rub against trees and fence posts, producing raw, ulcerate skin lesions which are attractive to bush flies and these provide a further source of worry. It is likely that buffalo flies are the intermediate host for Stephanofilaria spp. which can be associated with granul wounds of the skin.

Diagnostic Information: The fly can be identified by its dark grey colour, size (3.5 – 4mm long), with two well-defined dark stripes on the thorax and a bayonet-like proboscis that protudes forward from the head.

Control: Fly traps, impregnated ear tags, dipping with insecticide, and use of macrocyclic lacot fi invermectin are used. Ivermectin in a pour-on formulation will control infestation for up to 21 days after treatment.