The twelve-spotted ladybird beetle, Coleomegilla maculata lengi, is commonly found in
potato fields where it feeds on Colorado potato beetle eggs, aphids, and lepidopteran eggs.
M-One (Bacillus thuringiensis var. san diego) is commonly used on potato to control
Colorado potato beetle larvae. Fortunately, M-One is not lethal to C. maculata larvae even at
10 times the recommended field concentration and C. maculata predation is not significantly
affected by M-One either. Larvae consumed an average of 2.1 Colorado potato beetle eggs
treated with M-One per day and adults attacked 12.0 eggs per day in laboratory studies. The
effects of M-One on reproduction and fertility were not studied; its effects on successive
generations needs to be studied before the innocuousness of this biopesticide to C. maculata can
be concluded.
Source: Giroux, S., D. Coderre, C. Vincent, and J.-C. Cote. 1994. Effects of
Bacillus thuringiensis var. san diego on
predation effectiveness, development and mortality of Coleomegilla maculata lengi (Col.: Coccinellidae) larvae.
Entomophaga 39(1): 61-69.
