ESTABLISHMENT OF OLESICAMPE-GENICULATAE QUEDNAU AND LIM (HYMENOPTERA,ICHNEUMONIDAE) TO CONTROL THE MOUNTAIN ASH SAWFLY, PRISTIPHORA-GENICULATA (HARTIG) (HYMENOPTERA, TENTHREDINIDAE), IN NEWFOUNDLAND

Mated female Olesicampe geniculatae Quednau and Lim were released in S t. John's, Newfoundland, to establish a biological control against the mountain ash sawfly, Pristiphora geniculata (Hartig). Two hundred and fifty-nine females were released during 1981-1984 in a field cage con structed over a mountain ash tree and provided with thousands of host larvae; 171 females were released outside the cage in 1984. A second o pen release of 368 P. geniculata cocoons, obtained as larvae from the field cage and presumably parasitized by O. geniculatae, was made in 1 986 at Pasadena in western Newfoundland. Olesicampe geniculatae rapidl y established in the St. John's area where host populations dropped to insignificant levels by 1990. Island-wide monitoring during 1989 and 1990 indicated that O. geniculatae had spread to the west and south co asts, at rates as high as 50 km per year. Effective and persistent sup pression of P. geniculata by O. geniculatae is anticipated.