THE GREEN APPLE APHID, APHIS-POMI DEGEER (HOMOPTERA, APHIDIDAE), AS PREY OF POLYPHAGOUS ARTHROPOD PREDATORS IN ONTARIO

In Ontario several species of polyphagous arthropods consumed nymphs and apterous adults of the green apple aphid, Aphis pomi DeGeer, as determined by serological assays and feeding trials. The most abundant predators on apple tree foliage were the reduviid Acholla multispinosa L., the mirid Campylomma verbasci (Meyer), the coccinellids Coccinella septempunctata L. and Adalia bipunctata L., and coccinellid and chrysopid larvae. An efficacy index developed to assess the effectiveness of foliage-inhabiting predators indicated that those with the greatest potential were Chrysopa larvae and adult C. septempunctata in 1987, and adult C. septempunctata and C. verbasci in 1988. The earwig, Forficula auricularia L., showed potential as a predator of A. pomi in 1989. Of the epigeal arthropods tested, the carabids Amara aenea DeGeer, Bembidion quadrimaculatum oppositum L., and Harpalus aeneus F., and the ants Formica fusca group, Myrmica ameryana Forel, and M. monticola Wheeler were the most active feeders on A. pomi.