PATHOGENICITY OF BEAUVERIA-BASSIANA (BALS) VUILL AND VERTICILLIUM-LECANII (ZIMM) TOWARD BLISTER BEETLE, LYTTA-NUTTALI SAY (COL, MELOIDAE)

In the Saskatchewan prairies Nuttall blister beetle Lytta nuttali Say is a sporadic pest of forages, canola, faba beans (Vicia faba) and a v ariety of other crops like lupin (Lupinus spp.) and vetch (Vicia sativ a). In this study we examined the effectiveness of various B. bassiana strains isolated from Russian wheat aphid, Diuraphis noxia (Mordv.) ( DN 8806 and DN 8804); the greenbug, Schizaphis graminum (Rond.) (SG 86 01, SG 8702, SG 8701) and GK 2016, USSR 2553; DAOM 210569, DAOM 144746 ; DAOM 71453; ATCC 44860 and Verticillium lecanii ATCC 46578. B. bassi ana strain SG 8702 proved to be the most effective. Different strains of B. bassiana used in this study were found more pathogenic to Nuttal l blister beetle than V. lecanii. Bioassays conducted using conidiospo res, blastospores or its extracellular fraction with SG 8702 showed ef fective mortality. The results revealed that possibly fungal toxins ma y be involved in the early mortality observed with some B. bassiana is olates.