Effects of contact insecticides pirimifos-methyl and deltamethrin of Indian meal moth Plodia interpunctella Hbn. and Angoumois grain moth Sitotroga cerealella Oliv. in maize, and on bean weevil Acanthoscelides obtectus Say in beans were examined 6 and 18 months after treatment in laboratory environment. Using appropriate methods (EPPO and other), maize and bean were treated with recommended and double rates of the insecticide products: EC formulation of pirimifos-methyl and EC formulation and dust of deltamethrin. After 6 and 18 months, we examined the mortality of P. interpunctella larvae, and 5. cerealella and A. obtectus adults following 2,7 and 14 days of contact with the treated material. In Angoumois grain moth and bean weevil, the resulting progeny was monitored up to FI generation. Both insecticides achieved full mortality of P. interpunctella larvae on the 6-month-old deposit. On the 18-months-old deposit, the same result was achieved with deltamethrin dust (both rates), as well as with pirimifosmethyl and deltamethrin (EC formulation) at the double recommended rates. S. cerealella mortality was 100% for both insecticides and both deposit ages. Regarding A. obtectus, full mortality of adults was found after contact with pirimifos-methyl and deltamethrin dust, while deltamethrin liquid caused low mortality of bean weevil, especially the 18-months-old deposit. FI generation adults of Angoumois grain moth and bean weevil were found only on 18-months-old deposits of the recommended rates of deltamethrin dust and pirimifos-methyl. The tested contact insecticides can provide very long prevention and control of Indian meal moth and Angoumois grain moth in stored maize and bean weevil in stored beens.
Importance, Biology, Damage and Management of Bean Weevil Acanthoscelides obtectus Say (Coleoptera: Chrysomelidae)