Insecticide resistance in field populations of the legume pod-borer, Maruca vitrata Fabricius (Lepidoptera: Pyralidae), on cowpea, Vigna unguiculata (L.), Walp in Nigeria

caupi cihalotrina cipermetrin cowpeas cyhalothrin cyhalothrine cypermethrin dimethoate dimetoato endosulfan insecticidas insecticide insecticides lambda-cyhalothrin lepidoptera maruca maruca vitrata nigeria pyralidae resistance to chemicals vigna vigna unguiculata