Parasites of the Frit-fly, Oscinella frit (L.), in eastern North America

Abstract

An account is given of an investigation made of the life-histories of Oscinella frit and its parasites in Ontario, Canada, with a view to the possible introduction of suitable parasites into England. The various Chloropid species associated with O. frit in North America are discussed.The life-history of the frit-fly in Ontario is similar to that in England except wheat, not oats, is attacked, and that there appears to be no regular grain-infesting generation, but the insect is never a major pest in Canada.The life-histories of the following six species of parasites are described : Hexacola sp. n., Polyscelis sp. n., Loxotropa sp., Cyrtogaster sp., Callitula bicolor and Spalangia drosophilae. Other hosts from which these parasites have been reared include Chloropids associated with O. frit in wheat, namely O. carbonaria, O. soror, O. minor and Meromyza americana.A brief account is given of the control exerted by these parasites on the population of frit-fly in Ontario and a comparison is made between the Canadian and English parasite complexes. From this it is concluded that S. drosophilae might exert some control of frit-fly if introduced into England.