Control of headfly on sheep.

Headfly caused irritation to sheep in Northumberland from late June of each year 1973 to 1975. Numbers of headflies caught in sweep nets declined sharply from early August 1973 and 1975 but remained fairly high in 1974 until mid September. Attacks on sheep followed a similar pattern. The effectiveness of a number of fly repellent applications was examined. Headcaps gave good and sometimes complete protection.