Abstract:

Toxic test of thirteen pesticides on Hyphantria cunea 3rd instar larvae by immersion method was evaluated in laboratory. The results revealed mortalities of larvae were all reached 100% with the treatment of 20% methomyl WP after 24h, three chrysanthemum cinerariaefolium and 1.1% matrine?nicotine AW after 36h, besides 80% DDV EC after 48h. Followed, 1.8% abamectin Ec in 72 h gave 98.2% mortality rate on Hyphantria cunea (Drury) with the dilution of 4000 time, while 25% chlorbenzuron Ⅲ WP and 0.3% baoshuoⅠAS after 72honly provided 12.71%-39.99% mortality rate against the pest with the dilution 1500-4500 time .And the pest mortality rate was lower with the treatment of the other two bionic and botanical pesticides after 72h. Furthermore , toxticity regression equation of the thirteen pesticides on larvae was fitted well and values of LC50 were calculated.