Three Organophosphate Insecticides on Mulberry Thrips Control and Their Residual Toxicities on Silkworm

Naled 50% EC,dimethoate 40% EC,and dichlorvos 80% EC were tested against mulberry thrips in a field trial. Mulberry leaves were collected 1,3 and 7 days after application of these pesticides and fed to silkworms in order to determine their residual toxicities. The results showed that the three pesticides were effective on thrips control,and the leaves were safe for silkworms 3 d after application. The naled treatment had a similar moulting rate and cocoon weight to the control. These parameters were lower in the dimethoate and dichlorvos treatments. Naled dosage was suitable in 500-333 mg/kg and 3 d after applying was safe for silkworm,400 mg/kg dimethoate and 800 mg/kg dichlorvos with 7 d after applying is safe.