Laboratory Bioassay of some Insecticides as Contact Poison against Third Instar Larvae of <I>Glyphodes pyloalis</I> Walker (Lepidoptera : Pyralidae)

Abstract

The nineteen conventional insecticides were tested as contact poison against third instar larvae of Glyphodes pyloalis in laboratory. The descending order of toxicity of the insecticides was : chlordimeform> formotbion > quinalphos >monocrotophos> toxaphene> carbaryl> fenitrothion> malathion (premium grade) :> methyl parathion > endosulfan > malathion + fenitrotbion > leptophos :> klofos :>dichlorvos > endosulfan > DDT > dimethoate> pyretbrum>chlordane>gamma-BHC. Monocrotophos, formothion and chlordimeform are 27 to 32 times more toxic than DDT. Relative resistance to these insecticides of Glyphodes pyloalis than Selepa celtis is also discussed.