Effects of chlorantraniliprole on development and reproduction of beet armyworm, Spodoptera exigua (Hübner)

摘要

The lethal and sublethal effects of chlorantraniliprole against Spodoptera exigua (Hübner) were evaluated under laboratory conditions by oral exposure of neonate larvae to the compound. The 72 h LC₅₀ value of this insecticide to S. exigua was found to be 12.747 µg l−1. A progressive larval mortality of 24.32% for LC₃₀ treatment and 42.61% for LC₅₀ treatment was observed from 4th to 6th day after exposure, which resulted in the reduced pupation rates in exposure groups. The sublethal effects of this chemical were indicated by prolongation of larval period, the increase of pupal weight and decrease in hatch rate of egg. Chlorantraniliprole at LC₃₀ and LC₅₀ rate significantly delayed larval development; the developmental duration of surviving larvae was extended for 22.5 and 28.6%, respectively, compared with that of control group. LC₃₀ treatment increased the mean weight of pupa and induced to the production of heavier pupa (>150 mg). In LC₅₀ treatment, heavier pupa also showed up but the mean weight of pupa was not influenced. The egg hatch rate in LC₅₀ group was significant lower than that in control and LC₃₀ groups. No significant differences in pupal duration, emergence rate, sex ratio, egg number per female, and longevity of adults were observed among treatments. Chlorantraniliprole had exceptional activity against S. exigua according to concentration–response bioassay in laboratory, and the toxicities were primarily resulted from immediate lethality.