Evaluation of the effects of two Beauveria bassiana (Balsamo) Vuillemin strains on the development of Coleomegilla maculata lengi Timberlake (Col, Coccinellidae)

The effect of the fungus Beauveria bassiana (Balsamo) Vuillemin, strains ATCC 44860 and ARSEF 2991, on the development of the spotted ladybird beetle Coleomegilla maculata lengi Timberlake larvae and pupae was evaluated at concentrations of 10(2), 10(4), 10(6) and 10(8) blastospores/ml. Duration of development of C. maculata was measured when fed on contaminated pollen or when allowed to prey on first and second instars Colorado potato beetle Leptinotarsa decemlineata Say (Col., Chrysomelidae) larvae treated by pulverization. The two B. bassiana strains exhibited different effects on the duration of development of C. maculata. Pollen or Colorado potato beetle larvae treated with B. bassiana strain ATCC 44860 increased the C. maculata development time, whereas Colorado potato beetle larvae treated with strain ARSEF 2991 reduced development time but pollen treated with the same strain had no effect.