ESTABLISHMENT AND SPREAD OF TETRASTICHUS JULIS (HYMENOPTERA: EULOPHIDAE), A PARASITOID OF THE CEREAL LEAF BEETLE IN ONTARIO

Abstract
Tetrastichus julis (Walker), a European larval endoparasite of the cereal leaf beetle, Oulema melanopus (L), has become widely established in southern Ontario. In 1975, rates of parasitism in 14 counties varied from 15% in the east to 95% in the west Dispersal into Ontario was natural and is attributed to extensive colonization of the parasitoid in Michigan and other parts of the U.S. midwest. Reasons for its success in Ontario are suggested.