Effects of temperature on baseline susceptibility and stability of insecticide resistance against Plutella xylostella (Lepidoptera: Plutellidae) in the absence of selection pressure

摘要

L. (Lepidoptera: Plutellidae) is an important pest causing significant losses to vegetables worldwide. Insecticides resistance in is a serious issue for scientists since last 30 years. However, deltamethrin and are commonly used insecticides against but studies involving development of resistance in against these two insecticides at different temperatures are lacking. The current study was aimed to find out the toxicity of deltamethrin and , and resistance development in . Results showed that the positive correlation between the temperature and toxicities of deltamethrin and . The results indicated −0.051, −0.049, −0.047, and −0.046 folds of deltamethrin resistance at 15 °C, 20 °C, 25 °C, and 30 °C temperatures, respectively from 1 to 12 generations. The toxicity of after 24 h was 2.2 and 4.8 folds on 1 generation at 20 °C and 25 °C temperatures, respectively compared to the toxicity recorded at 15 °C (non-overlapping of 95% confidence limits). Based on the results of this study, it is concluded that the temperature has a positive correlation with the toxicity of deltamethrin and against the larvae of This study suggests that deltamethrin and can be included in the management program of on many vegetable crops The baseline susceptibility data might be helpful to understand the resistance mechanisms in .