Capsaicin as an Organophosphate Synergist Against Colorado Potato Beetle (Leptinotarsa Decemlineata Say)

Abstract

The aim of the presented study was to assess the applicability of capsaicin as a synergist for organophosphate insecticide against the Colorado potato beetle (Leptinotarsa decemlineata Say). We recorded the death rate, behavioral thermoregulation and meta- bolic rate of the examined insects after intoxication with capsaicin and organophosphate pesticide. The results obtained showed that the tested substances changed the thermal preferences of the potato beetle, causing the beetles to prefer a decrease in temperature in the thermal gradient system. We also observed an increase in the metabolic rate of the beetles intoxicated with capsaicin and or- ganophosphate insecticide. The addition of capsaicin in a concentration of 10 -7 M (dissolved in alcohol) to insecticide resulted in an increase in the death rate of the insects by 24% in 35°C and 73% in 15°C, in comparison to organophosphate alone. Our results show that capsaicin in low concentrations may be an efficient synergist for organophosphate insecticides against the Colorado potato beetle.