The sheep nose bot fly is a large, robust fly with
a large head. Females deposit live
larvae in the nostrils of sheep. The
larvae migrate to the head sinuses and after completing development, migrate
back down the nasal passage and drop to the ground and pupate, from which the
adult fly emerges. There may be two
generations per year in temperate areas.
The bot fly “strike” when flies deposit larvae,
causes irritation to sheep as does the migration of the larvae to and from the
head sinuses. Infested sheep bang their
heads on the ground, feed bunks or fence posts.
Membranes of the nasal passages and sinuses are irritated by the bot larvae, and this may result in bacterial infections.
Lamb weight gain performance can be reduced by as much as 4% from nose bot infestations.
There is one registered insecticide for control of the nose bot, and that is ivermectin as a 0.08% sheep drench solution. It can be applied with standard animal health drenching equipment at a dose of 3.0 ml per 26 lb. animal body weight.
Categories: Livestock insects, Sheep, Goats, Sheep
nose bot
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