The effect of host plant on colorado potato beetle (coleoptera: Chrysomelidae) susceptibility to pyrethroid insecticides

In laboratory studies, Colorado potato beetle (CPB) (Leptinotarsa decemlineata Say) reared on eggplant were significantly more susceptible to permethrin than CPB reared on tomato. Field studies conducted in 1984 and 1985 showed that the percentage reduction of CPB larvae reared on eggplant due to foliar applications of fenvalerate was significantly greater than the percentage reduction of CPB larvae reared on either potato or tomato. Plant defoliation was greater on eggplant and potato than on tomato. Eggplant and potato yields increased as the dose of fenvalerate increased and the potato beetle population decreased, but tomato yields were unaffected by fenvalerate treatments. The effects and biological activity of individual plant chemical compounds (i.e., glvcoalkaloids) in various Solanum species need to be examined in detail before the full significance of the role of these compounds in host‐plant resistance and their interaction with CPB insecticide resistance are understood.