Bioassay ofMetarhizium anisopliae,Beauveria bassiana, andNeoaplectana carpocapsaeAgainst Larvae of the Plum Curculio,Conotrachelus nenuphar(Herbst) (Coleoptera: Curculionidae)1

Abstract

Plum curculio larvae, Conotrachelus nenuphar (Herbst), were treated in the laboratory with isolates of the fungi Metarhizium anisopliae (Metschnikoff) Sorokin and Beauveria bassiana (Balsamo) Vuillemin, and the namatode Neoaplectana carpocapsae Weiser. Both isolates of the fungi caused high levels of mortality in curculio larvae. The nematodes were ineffective under the conditions tested. Soil treated with comminuted suspensions of shake or agar plate cultures of isolates of M. anisopliae from South Carolina and California and an isolate of B. bassiana from South Carolina indicated little difference between culture preparation methods but greater pathogenicity by M. anisopliae from South Carolina. Metarhizium anisopliae was more effective than B. bassiona in soil treated 3 days previous to larval introduction. Maximum effects by the fungi were not always apparent until 14 days after treatment. Handling larvae during examination at 6 days did not cause additional significant mortality 8 days later.