Heat and Conventional Insecticides Frank H. Arthur USDA-ARS-GMPRC Manhattan KS 66502
Spot, Crack & Crevice Treatments zOrganophosphate and pyrethroid insecticides are used as spot or crack & crevice treatments zSpecific language on the label defining a spot (often 2 ft 2 or less) Specific directions for crack & crevice applications
General Surface Treatments zSpray volume and area are specified z1 gal of formulated spray per 1,000 ft 2 zDifferent label language and application directions zLimited number compared to crack & crevice
Insecticides zMalathion: OP, not being reregistered zCyfluthrin EC & WP (Tempo): pyrethroid zHydroprene (Gentrol): insect growth regulator
Residual degradation or inactivation zOPs degrade as temperature increases zSummer degradation is a serious problem with grain protectants zResidues drop below levels that will control insects zExample: degradation at controlled temperatures
Degradation of chlorpyrifos- methyl on wheat (values in ppm)
Pyrethroids zMore heat-stable compared to OPs zDegrade primarily by UV light zExample: wheat treated with chlorpyrifos-methyl and deltamethrin zWheat stored in a metal shed from Oct- July in south GA zMean monthly temp was °C during the study
Degradation of chlorpyrifos-methyl (CM) and deltamethrin (D) on wheat stored for 10 months (values in ppm)
Heat treatments and insecticides zInsecticide would probably degrade rapidly at °C zPyrethroids a more practical choice
Cyfluthrin WP zGives better residual control on porous surfaces than cyfluthrin EC zCommon treatment in food warehouses and other indoor structures zWill extreme temperatures associated with heat treatments affect residual efficacy?