Release and establishment studies in Manitoba, Canada, of Aphidius smithi (Hymenoptera: Aphidiidae), a parasitoid of Acyrthosiphon pisum (Hemiptera: Aphididae)

Abstract

AbstractAphidius smithi Sharma et Subba Rao, an aphidiid parasitoid of the pea aphid, Acyrthosiphon pisum (Harris), was imported into Manitoba, Canada, and over 104 000 adults were released at four sites in 1983–1987. The parasitoid reproduced and overwintered at the 1983 release site and possibly at a second site at which it was released in 1984, and reproduced at two other sites at which it was released in 1985–1987. The parasitoid was found in 1985 up to 11 km from the 1983 release site. Additional studies in 2001 indicated the presence of low densities of A. smithi near one of the 1985 release sites. Although the parasitoid is established, it occurs at densities too low to have an agriculturally useful effect on the pest.