Sublethal effects of sulfoxaflor on population projection and development of the white-backed planthopper, Sogatella furcifera (Hemiptera: Delphacidae)

Sogatella furcifera (Horvath) (Hemiptera: Delphacidae) is a very destructive insect pest occurring in rice, and has developed highly resistances to frequently-used insecticides. Sulfoxaflor is a novel insecticide that can be used to control S. furcifera. In general, the effects of the sublethal concentrations of a new insecticide on the population growth and reproduction of the target insect pest is indispensable before it is widely used in practice. The toxicity of sulfoxaflor on 3rd-instar nymphs of S. furcifera was assayed using dipping seedling bioassays, and the results showed that the LC10 and LC25 of sulfoxaflor were 1.285 mu g/mL and 2.102 mu g/mL at 96 h after treatment, respectively. The effects of two sublethal doses on age-stage two-sex life table parameters of the F1 generation of S. furcifera were assayed and the results indicated that the developmental duration of S. furcifera pre-adult, adult, female adult longevity and the total preoviposition period (TPOP) treated with LC10 dose were all significantly prolonged compared to the control or the LC25 dose. The mean fecundity for LC10 dose of sulfoxaflor (233.0 eggs/female) was significantly more than those of the control (168.1 eggs/female) and LC25 (140.8 eggs/female). There were no differences in the intrinsic rate of increase (r) and finite rate of increase (lambda) of S. furcifera among the three treatments, whereas the net reproductive rate (R-0) of S. furcifera treated with LC10 was higher than those in the control or the LC25 dose. The mean generation time (T) for the LC10 treatment was the longest (29.25 d), followed by the treatments of LC25 (27.29 d) and the control (26.16 d), and differed significantly from each other (P < 0.05). Our findings have revealed that S. furcifera had stronger fertility under the pressure of low sublethal concentrations of sulfoxaflor. These finding provide theoretical assistance for Integrated Pest Management (IPM) strategy to control S. furcifera in the field.