Abstract
Research on operational use of Bacillus thuringiensis 3a3b against spruce budworm, Choristoneura fumijerana (Clem.), led to the development of a concentrated B. thuringiensis formulation containing the required potency of 20 B.I.U. of B. thuringiensis in a final volume of 4.7 l./ha (Smirnoff 1978). Aerial operational applications of this formulation were highly effective against the spruce budworm and resulted in acceptable foliage protection (Smirnoff 1979, 1980a). However, it is felt that B. thuringiensis will be used extensively against C. fumiferana only when its cost is lowered to that of chemical insecticides. heref fore, several B. thuringiensis + chitinase formulations were developed leading to an even more concentrated B. thuringiensis formulation, which we call Futura, in which the required 20 B.I.U./ha is applied in a final volume of 2.5 l./ha. We describe the composition of Futura and discuss the bacteriological and physical qualities of the formulations and its efficacy.