CONTROL OF THE COLORADO POTATO BEETLE WITH AUGMENTATIVE RELEASES OF THE STINKBUG PERILLUS BIOCULATUS

Abstract

Tests in experimental plots over two seasons have shown that it is possible to obtain excellent control of eggs and larvae of the Colorado potato beetle (CPB) (Leptinotarsa decemlineata) under Quebec growing conditions by augmentative releases of a generalist predator, the twospotted stinkbug P. bioculatus. The stinkbugs were mass-reared on CPB eggs and larvae in the laboratory, and were released as second or third instar nymphs at the time of peak beetle oviposition. They were introduced manually at ratios of 2-4 predators : beetle egg mass in plots comprising ≈1000 `Kennebec' potato plants. Short-interval sampling after introduction indicated good rates of establishment and survival of the released P. bioculatus nymphs. Analysis of CPB egg recruitment and mortality indicated high rates of destruction of CPB eggs by the stinkbug. Egg destruction was followed by significant predation of late-instar bugs on CPB larvae, resulting in significant reductions of CPB prepupal and adult densities, and excellent foliage protection in treated plots compared to untreated controls. The results will be discussed with reference to traits of P. bioculatus that make it a good candidate for biocontrol of the CPB, and to problems yet to be resolved before augmentative releases of the predator can be used as an integrated pest management tactic in larger scale potato production.