Persistence Bioefficacy of Insecticides Against Callosobruchus chinensis (L.) on Cowpea

The present investigation was undertaken to study the persistence of different insecticides as seed treatment against pulse beetele Callosobruchus chinesis. The insecticide treated cowpea seeds were exposed at monthly interval to the infestation by pulse beetele Callosobruchus chinesis to test the persistence of insecticides. The mortality of insect due to the toxicity of insecticides and adult emergence were the main criteria for testing the persistence of different insecticides. Persistence of insecticides on pulse beetele C. chinesis in storage condition revealed that among different insecticides Spinosad and Deltamethrin were found to be most effective and provided protection up to 6 months of storage period based on probit analysis. Malathion and Fenvelerate were found to be least effective which did not give protection for longer duration. Among all insecticides Spinosad @ 2ppm and deltamethrin @ 3 ppm recorded lowest adult emergence of pulse beetele C. chinesis. Malathion @ 20 ppm recorded highest population buildup.