Bioactivity of 6 Insecticides to Different Developmental Stages of Plutella xylostella(L.)

Bioactivities of chlorfenapyr, lufenuron, chlorantraniliprole, indoxacarb, abamectin and spinosad to eggs, larvae, pupae and adults of Plutella xylostella were studied by egg-dipping method, leaf-dipping method, immersion method and residual film method in the laboratory. The results showed that the six insecticides had excellent effects on larvae of P. xylostella. Chlorfenapyr and spinosad had quick bioactivities after 24 h treatment, and the corrected mortalities were above 90%. The corrected mortalities of chlorfenapyr, chlorantraniliprole, abamectin and spinosad reached 100% after 72 h treatment, the corrected mortality of indoxacarb were 98.2%. All of the six insecticides had certain ovicidal effects, ovicidal activity of lufenuron was high, abamectin and spinosad had low ovicidal activities, but could kill neonate larvae and decrease survival rates of larvae. The survival rates of 2nd instar larvae were below 10% after eggs treated with field doses of all six insecticides. Among six insecticides, chlorfenapyr and indoxacarb showed higher toxic to pupae and adults of P. xylostella, the other four insecticides had a little or no toxic to pupae and adults of P. xylostella.