| Aimed at the problem of pesticides toxicity to Bombyx mori Linnaeus , the acute toxicity of general pesticides and especial insecticides to Bombyx mori and the safety evaluation were studied ; the effect to growth and development of Bombyx mori dealed with low dose of especial insecticides were studied ; the comparison on toxity selectivity of chlorfenapyr between Bombyx mori and mulberry pestes was studied ; the enzyme activity of different instar of Bombyx mori were determined; the enzyme activity of the fouth instar Bombyx mori dealed with dichlorvos and methomyl were measured; the enzyme activity of the 4 instar lavae of Bombyx mori and Spodoptera exigua Hübener were researched also in the article.The results could be summarized as followings :1. The acute toxicity of thirty pesticides to Bombyx mori were evaluated in laboratory using Leaf dipping method ; the grade was compartmentalized according as toxicity scope and the safety evaluation were made for these pesticides .The results indicate that the LC50 of three insecticides were lower than 0.1 mg·L-1, belong to special high toxicity grade;that of nine insecticides between 0.110 mg·L-1, belong to high toxicity grade ; that of eight pesticides between 101000 mg·L-1, belong to middling toxicity grade ; that of ten pesticides higher than 1000 mg·L-1 , belong to low toxicity grade .2. The acute toxicity of four especial insecticides to Bombyx mori were evaluated in laboratory using food intake method and the safety were evaluated . The results indicate that the LC50 in 24h of hexafluron , chlorfluazuron , tebufenozide , methoxyfenozide and chlorfenapyr were 425.77 , >1000 , >1000 and 320.58 mg·L-1, respectively ; the LC50 in 48h were 0.3509, 0.6644, 145.80 and 10.480mg·L-1, respectively ; the LC50 in 96h were 0.02735, 0.03857, 0.2863 and 0.4175 mg·L-1 eachly . Sothat , hexafluron and chlorfluazuron have very high risk to Bombyx mori ; tebufenozide andmethoxyfenozide have high risk to Bombyx mori.
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