SYNERGISM BETWEEN CRYIA INSECTICIDAL CRYSTAL PROTEINS AND SPORES OF BACILLUS-THURINGIENSIS, OTHER BACTERIAL-SPORES, AND VEGETATIVE CELLS AGAINST LYMANTRIA-DISPAR (LEPIDOPTERA, LYMANTRIIDAE) LARVAE

The lethality of CryIA(a) and CryIA(c) insecticidal crystal proteins f rom Bacillus thuringiensis to gypsy moth, Lymantria dispar (L.), was s ignificantly enhanced by the presence of either bacterial spores or ve getative cells of Escherichia coli and several forest epiphytic bacter ia. Spores from B. cereus, B. megaterium, and B. subtilis were as effe ctive synergizers of the CryIA insecticidal crystal proteins as spores from an acrystalliferous strain of B. thuringiensis (HD-73 cry(-)). K lebsiella sp., K. pneumonia, Erwinia amylovora, E. rubrifaciens, Pseud omonas fluorescens, Xanthomonas sp., X. campestris, Actinomyces sp. Co rynebacterium sp., Flavobacterium sp., and Escherichia coli were effec tive synergizers of at least one of the CryIA toxins. Only P. syringae was not synergenic. In the absence of the CryIA toxins, none of the b acterial cell or spore synergists exhibited toxicity or inhibited larv al growth or molt to the next instar.