Evaluation of indoor virulence of 17 insecticides against Cacopsylla chinensis nymphs in Korla fragrant pear orchards

Objective This study aimed to conduct indoor efficacy tests of insecticides against Cacopsylla chinensis in Korla fragrant pear orchards, record the mortality of C. chinensis under different insecticidal treatments, screen out low-toxicity and high-efficiency insecticides for C. chinensis control, and provide a scientific basis for its management.

Methods In this experiment, 17 commonly available insecticides were selected at their conventional dosages for indoor efficacy tests against C. chinensis nymphs. The systemic insecticidal effect of each tested insecticide was determined using the tube residual method, the contact effect was determined using the spray method, and the stomach poisoning effect was determined using the leaf-dipping method.

Results Among the 17 insecticides, imidacloprid exhibited the strongest contact toxicity, with an LC₅₀ value of 1.262 mg/L, and C. chinensis nymphs showed the weakest contact resistance to it. Matrine exhibited the strongest systemic and stomach poisoning toxicity against C. chinensis nymphs, with LC₅₀ values of 1.913 and 0.890 mg/L, respectively. Nitenpyram ranked second only to imidacloprid in contact toxicity and sensitivity concentration, with a contact LC₅₀ of 1.332 mg/L, and the nymphs showed the weakest stomach poisoning resistance to it.

Conclusion Matrine, nitenpyram, and imidacloprid exhibited strong toxicity against C. chinensis nymphs, and are therefore recommended for practical application.