Toxicity of neonicotinoid insecticides against Dysmicoccus neobrevipes.
Dysmicoccus neobrevipes is an invasive pest found in China in recent years. It is also one of the main pests of Sisal. The purpose of this study was to screen effective insecticides for control of D. neobrevipes. Toxicities of acetamiprid, dinotefuran, clothianidin, thiamethoxam and nitenpyram were evaluated against D. neobrevipes female adults and different instar nymphs with spraying method. Results showed that five neonicotinoid insecticides had obvious contact toxicity to different instars of D. neobrevipes. Toxicity of the same insecticide against D. neobrevipes decreased as the insects grew. Among them, nitenpyram displayed the highest toxicity against D. neobrevipes. The LC50 values of nitenpyram against 1st, 2nd, 3rd instar nymphs and female adults of D. neobrevipes were 0.1406 mg/L, 0.155 mg/L, 0.3870 mg/L, and 0.5060 mg/L, respectively. The toxicities of acetamiprid and thiamethoxam were lower than that of nitenpyram, and the toxicities of dinotefuran and clothianidin were the lowest. Sensitivity of D. neobrevipes at different star to the same insecticide was shown as follows 1st nymph > 2nd nymph > 3rd nymph > female adults. The results of this study indicate that nitenpyram has the best contact toxicity, which can be used as an alternative insecticide to control D. neobrevipes.