Bioassay Techniques and Response of Different Populations of Amrasca biguttula biguttula Towards Commonly Used Insecticides in Kerala

A comparison of two bioassay techniques for evaluating toxicity of different insecticides against Amrasca biguttula biguttula Ishida infesting bittergourd indicated that the leaf-dip method is better compared to the spray residue method. Studies on the susceptibility of different populations oM. biguttula biguttula collected from four district of Kerala to five insecticides revealed that Vellanikkam population was most susceptible to quinalphos, monocrotophos, and phasolone in both farmers’ fields and homestead gardens. Carbaryl caused highest mortality to populations from farmers’ fields while lowest mortality was observed in homestead garden populations. No significant differences were observed in mortality of leaf hopper populations from farmers fields and homestead gardens.