Coleomegilla maculata (Cole opera: Coccinellidae): Its Predation upon the Colorado Potato Beetle (Coleoptera: Chrysomelidae) and Its Incidence in Potatoes and Surrounding Crops

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Abstract
The polyphagous coccinellid Coleomegilla maculate DeGeer fed on eggs and small larvae of the Colorado potato beetle, Leptinotarsa decemlineata (Say). Prey consumption rates were highly correlated with temperature. This predator did not prefer aphids over potato beetle larvae in choice tests, but consumption of larvae decreased as aphid densities increased. Field cage studies demonstrated that C. maculata adults can significantly reduce populations of Colorado potato beetle eggs and small larvae. The incidence of C. maculata adults was monitored in early- and late-planted potatoes (Solanum tuberosum) in Rhode Island and Michigan. This predator coincided with first-generation Colorado potato beetle prey in early-planted potatoes in both states and with second-generation potato beetle prey in late-planted potatoes in Rhode Island. C. maculata also was found in cole crops, snap beans, cucurbits, and sweet corn in 1986 and in alfalfa and sweet corn in 1987, and the highest densities were observed in sweet corn during pollen production. Using observed temperatures and phenological models from the literature, we determined that C. maculata has the potential to complete two or three generations per year in Rhode Island and three or four generations per year in Michigan. The actual number of generations is probably dependent on its residence and dynamics in several adjacent crops.