Sublethal effects of pymetrozine on the development, reproduction and insecticidal susceptibility of Sogatella furcifera (Hemiptera: Delphacidae) (In English)
LONG Gui-Yun1, LIU Lei-Lei1, YANG Hong1, 2, WANG Zhao1, 3, JIN Dao-Chao1, *, ZHOU Cao1
(1. Institute of Entomology, Guizhou University/Provincial Key Laboratory for Agricultural Pest Management of Mountainous Regions, Guiyang 550025, China; 2. College of Tobacco Science of Guizhou University, Guiyang 550025, China; 3. College of Environment and Life Sciences, Kaili University, Kaili, Guizhou 556011, China)
Abstract 【Aim】 The white-backed planthopper, Sogatella furcifera (Horváth) (Hemiptera: Delphacidae) is an important insect pest of rice. The present study aims to determine the sublethal effects of pymetrozine on the development and reproduction of this insect and its susceptibility to other insecticides. 【Methods】 The life table method was used to evaluate the sublethal effects of pymetrozine (LC10 and LC25) on developmental duration, survival rate, emergence rate and longevity of F0 and F1 generations of S. furcifera and rice stem dipping method was adopted to determine its susceptibility to other insecticides after pymetrozine (LC10 and LC25) treatment. 【Results】 The developmental duration of the F0 generations of S. furcifera treated with sublethal concentrations (LC10 and LC25) of pymetrozine for 48 h was increased by 1.98 d and 4.25 d, the longevities were shortened by 0.49 d and 1.73 d, the survival rates (85.00% and 68.50%, respectively) of the 3rd-5th instar nymphs and the emergence rate (75.89% and 67.78%, respectively) decreased as compared with the control (92.00% and 85.90%, respectively), but significant difference was just observed in generation duration between the LC25 treatment group and the control. Furthermore, the F1 generation of S. furcifera exposed to sublethal concentrations (LC10 and LC25) of pymetrozine for 48 h had decreased emergence rate (76.97% and 68.94%, respectively), copulation rates (77.79% and 66.44%, respectively), egg hatching rates (73.19% and 68.67%, respectively), fecundity (112.36 and 88.34 eggs laid per female, respectively), and relative fitness (0.41 and 0.20, respectively) as compared with the control (88.22%, 86.67%, 87.26%, 147.80 eggs laid per female and 1.00, respectively). The susceptibility of pymetrozine-treated S. furcifera to thiamethoxam, chlorpyrifos, and buprofezin showed that the LC50 values of the three chemicals were 2.16, 40.87 and 3.12 mg/L in LC10 treatment group, and 4.93, 17.96 and 8.39 mg/L in LC25 treatment group, respectively. The relative toxicity index (RTI) of thiamethoxam, chlorpyrifos and buprofezin to S. furcifera indicated that the susceptibility of pymetrozinetreated S. furcifera to these three insecticides was reduced. 【Conclusion】 Pymetrozine at sublethal concentrations can reduce the fecundity and population growth of S. furcifera and make it less susceptible to thiamethoxam, chlorpyrifos and buprofezin.
LONG Gui-Yun,LIU Lei-Lei,YANG Hong et al. Sublethal effects of pymetrozine on the development, reproduction and insecticidal susceptibility of Sogatella furcifera (Hemiptera: Delphacidae) (In English)[J]. ACTA ENTOMOLOGICA SINICA, 2017, 60(7): 790-798.