Toxicity and field control effects of eight biological pesticides against <italic>Stephanitis pyrioides</italic>

To screen out effective biological pesticides against the main pest Stephanitis pyrioides on Rhododendron plants, the toxicity of eight biological pesticides to adults of S. pyrioides was determined by leaf dipping method in laboratory, and the experiment of controlling nymphs and adults in forest was carried out. The results showed that the toxicity of azadirachtin 0.3 % soluble liquid (SL) and allicin 5% microemulsion (ME) to adults was stronger, the LC50 values were 2.568, 2.955 mg/L,respectively, and the LC50 value of 10 billion spores/g Metarhizium anisopliae suspension concentrate (SC) was 2.018×105 spores/mL. Rotenone 6% ME with mass concentration of 60, 120 mg/L and allicin 5% ME with mass concentration of 260.5 mg/L had good persistence and rapid effects. The control effects on nymphs were higher than 90% at 21 days after application, and the control effects on adults were higher than 90% at 14 days or 21 days after application, and there were no significant differences in the control effects between these two pesticides and thiamethoxam•lambda-cyhalothrin 12% SC with mass concentration of 160 mg/L. The results can provide reference for green prevention and control of S. pyrioides.