BACTERIOLOGICAL INSECTICIDE M-ONE EFFECTS ON PREDATION EFFICIENCY AND MORTALITY OF ADULT COLEOMEGILLA-MACULATA LENGI (COLEOPTERA, COCCINELLIDAE)

Laboratory experiments were done to determine whether the adult Coleomegilla maculata lengi Timberlake was affected by ingesting M-One, a commercial formulation of Bacillus thuringiensis var. san diego used to control the Colorado potato beetle, Leptinotarsa decemlineata (Say). Over a period of 10 consecutive days, consumption of pollen contaminated with 200 ml M-One per liter (5.6 x 10(9) CPBIU per liter) had no lethal effects on adult C. maculata. The level of predation by adult C. maculata on Colorado potato beetle eggs was reduced by M-One. At the manufacturer's recommended field rate of 20 ml M-One per liter (i.e., 5.6 x 10(8) CPBIU per liter), the number of eggs attacked was 37.0 and 14.5% lower than the untreated eggs, respectively, 3 and 24 h after the beginning of the test. The feeding behavior and results of a water versus 200 ml M-One per liter two-choice test suggest that the decrease in food intake caused by M-One cannot be explained by a delta-endotoxin-induced paralysis of the mouth parts or midgut.