In laboratory and greenhouse studies, the compatibility of a spore suspension of Beauveria bassiana (Balsamo) with insect growth regulators (IGRs) was determined. When B. bassiana was applied over residues of 7 different IGRs, infectivity of greater wax moth larvae, Galleria mellonella (L), exposed to leaf rinsates was reduced by two of the IGRs. Azadirachtin and diflubenzuron reduced the infectivity of B. bassiana by up to 50%. Fenoxycarb, cyromazine, S-kinoprene, pyriproxyfen, and buprofezin did not significantly reduce the infectivity of B. bassiana. Under greenhouse conditions, the population levels of green peach aphid, Myzus persicae (Sulzer), on chrysanthemums, were not significantly different when Botanigard® (B. bassiana strain GHA) was used independently or in combination with the IGR S-kinoprene. In laboratory tests, 100% of wax moth larvae were infected with B. bassiana when they were exposed to leaf washes 24 h post Botanigard application to chrysanthemum foliage. Infectivity decreased rapidly with less than 15% of the larvae infected with B. bassiana when exposed to leaf washes 48 hr post Botanigard application to foliage.
