Sheep Strike by the Fly, Phormia terrae-novae R.-D., in North-east Scotland

Abstract

DURING May–July, 1941, my colleague, Mr. W. Moore, who is studying pesticides in the North of Scotland College of Agriculture, Aberdeen, accidentally found the fly, Phormia terræ R.-D., attacking sheep in north-east Scotland. In the last week of May, when fly-strike had become fairly general, Mr. Moore decided to clean out and disinfect the breeding-chamber for flies and to restock it with a, fresh supply of the sheep maggot fly, Lucilia sericata Meigen, bred from maggots found on sheep. The first eleven batches of maggots were obtained from sheep on widely scattered farms. Each batch of maggots was reared under fly-proof conditions. The flies that emerged from the eleven batches of maggots were Phormia terræ R.-D. The species seemed the cause of primary strike in many cases. This is the first record of it striking sheep in north-east Scotland. Not until the second week of July did Mr. Moore obtain maggots of Lucilia sericata from sheep, and then he found it mixed with P. terrænovæ in two cases. Later strike by L. sericata seemed to become general.