Safety Evaluation of Six Kinds of Insecticides or Acaricides to Mulberry and Silkworm

The mulberry was sprayed respectively by six kinds of insecticides or acaricides( 10. 8% Abamectin · Pyridaben EC,40% Propyl bromide · Phoxim EC,90% Methomyl WP,24% Chlorfenapyr SC,40% Phoxim EC,and 73% Propargite EC)at different dosages in summer or autumn. The mulberry leaves on the 5th,8th,11th and 14th day after being sprayed were respectively used to feed on silkworm. The results showed that the two- time spraying did not produce phytotoxicity to mulberry. Except that there were poisoning or dead silkworms in the treatments of spraying the 1250- times,2500- times and 5000- times dilutions of 90% Methomyl WP,the toxic silkworms were not found in other treatments. Using the mulberry leaves sprayed by most insecticides or acaricides 5 ~ 11 days ago to feed on silkworm affected the quantity of whole cocoon and cocoon layer as well as the cocoon layer rate of silkworm to different extents. The mulberry leaves which were sprayed 14 days ago had no obvious effects on silkworm health and cocoon quality. Therefore,the insecticides must be strictly used according to their recommended concentration in the control of insect pests in mulberry field,and the mulberry leaves should be picked and used for silkworm after spraying insecticide for over 14 days.