Sublethal Effects Of Chlorantraniliprole And Avermectin On Growth Development And Fecundity Of Cnaphalocrocis Medinalis Guenee

Adult egg-dip assay, larva leaf-dip bioassay and pupa-dip assay were used to test the effect of sublethal concentration of chlorantraniliprole and avermectin on the growth, development and fecundity of eggs,1-5instars, pupa and Fo and F1generation of C.medinalis Guenee. The study provides scientific basis for the rational use of the two chemical pesticides.The two chemical pesticides showed no contact effect on eggs and pupa, the insecticide susceptibility of C. medinalis Guenee against the two pesticides decreased significantly with instar increased, the toxicity of Instar Ⅰ and Instar Ⅴ differed by a factor of73.55～547.21; Sensitivity of the first half year is higher than that of the second half year. The toxicity of avermectin is higher than chlorantraniliprole.The treatment of C. medinalis Guenee eggs disposed by sublethal concentration of chlorantraniliprole and avermectin showed no effect on the development, hatching eggs, adult emergence of the insect, pupal weight and eggs laid by per female of Fo generation. But it showed significant effect on the prepupa survival rate, especially after treated by avermectin, the prepupa survival rate were47.34%,46.77%,46.33%, respectively. It also showed significant difference between the control group-60.71%. The proportion of adult female was decreased, specifically the LC50treatment of chlorantraniliprole was significantly lower than the control group. There were no effect on the growth, development and fecundity of F1generation. Then the effect of hlorantraniliprole treatment showed no significant effect on the growth, development and fecundity of Fo and F1generation of C.medinalis Guenee.The results of treatment of C. medinalis Guenee1-5instars disposed by sublethal concentration showed that there were significant effect of LC25, LC50but little effect of LC10on the growth, development and fecundity of Fo generation. The larvae and pupa developmental duration were remarkably prolonged, and showed significantly difference with the control group; The pupal weight was decreased,1-2instars treatment have little effect on pupal duration and pupal weight, only LC50treatment on3-5instars was significantly lower than the control group. It showed great effect on survival rate, the prepupa survival rate was decreased, in addition to the LC50treatment on1-2instars had no effect on pupation rate, other treatments were significantly lower than the control group. As the effect on fecundity, eggs laid by per female was decreased, the longevity of adult was shortened, The proportion of adult female was decreased, but only LC50treatment of chlorantraniliprole on2-4instars treatment was significantly lower than the control group.The results of treatment of C. medinalis Guenee1-5instars disposed by sublethal concentration showed significant effect on the growth, development and fecundity of F1generation, but the effect was weakened, specifically the LC10and LC25treatments of avermectin have little effect. The larvae developmental duration was remarkably prolonged; the eggs developmental duration was prolonged, and the LC50treatment and LC25treatment of chlorantraniliprole on4-5instars treatments showed significant difference when compared with the control. As to the effect on pupa, the pupa developmental duration was prolonged, and1-3instars treatment had no effect on pupal weight, the LC50treatment on4-5instars was significantly lower than the control. The prepupa survival rate was significantly lower than the control, the hatching eggs and pupation rate were decreased, especially the LC50treatment was significantly lower than the control. Sublethal concentration of avermectin had no effect on adult emergence of C. medinalis Guenee, the LC50treatment of chlorantraniliprole was significantly lower than the control. As to effect on fecundity, eggs laid by per female was decreased, the longevity of adult was shortened, and the LC50treatment showed significant difference compared with the control; the proportion of adult female was decreased, but compared with the control was not significant.The effect of1-2instars treated by avermectin showed great effect on the growth, development and fecundity of F0generation. But it had less effect on F1generation. As to the3-5instars, the sublethal concentration of chlorantraniliprole showed great effect on C. medinalis Guenee, especially on the F1generation.