25种农药对家蚕的毒性评价和中毒症状观察

采用食下毒叶法,测定了18种杀虫剂、4种杀菌剂、2种除草剂和1种植物生长调节剂对家蚕的毒性,系统观察了杀虫剂处理家蚕后的中毒症状。结果表明:甲氨基阿维菌素苯甲酸盐、高效氯氰菊酯等14种杀虫剂的LC50值均小于0.5 mg/L,属剧毒级药剂,对家蚕有极高风险性;杀虫单和甲氧虫酰肼的LC50值分别为0.5493 mg/L和0.604 0mg/L,属高毒级药剂,对家蚕有高风险性;溴虫腈和丁醚脲的LC50值分别为72.370 mg/L和27.824 mg/L,属中毒级药剂,毒性较低;4种杀菌剂、2种除草剂和1种植物生长调节剂中仅有1种杀菌剂为中毒级,其余为低毒级,对家蚕的风险性较低;由不同杀虫剂引起的家蚕中毒症状表现出多种相似的特征,急性中毒主要特征有吐液、拒食、身体扭曲呈"C"或"S"形、静卧等,而蜕皮激素和几丁质合成的抑制剂类杀虫剂引起的家蚕中毒过程却比较缓慢。

Toxicity Evaluation of Twenty-five Pesticides to Bombyx mori and Observation of Toxi Symptoms

The acute toxicities of 25 pesticides to silkworm,Bombyx mori,were evaluated in laboratory by using the leaf dipping method including 18 pesticides,4 antiseptics,2 herbicides and 1 phytohormone.The toxi symptoms of silkworms after treatment of pesticides were systematically observed.The results indicated that the LC50 s of emamectin benzoate,β-cypermethrin etc.14 insecticides were lower than 0.5 mg/L,belonging to virulent toxicity grade;those of molosultap and methoxyfenozide 2 insecticides were 0.549 3 mg/L and 0.604 0 mg/L,respectively,belonging to high toxicity grade;those of chlorfenapyr and diafenthiuron 2 pesticides were 72.370 mg/L and 27.824 mg/L,belonging to middling toxicity grade and relatively lower than other insecticides.In the 7 pesticides including 4 antiseptics,2 herbicides and 1 phytohormone there was only 1 antiseptic belonging to medium toxicity grade and the other belonging to low toxicity grade.The observation of toxicosis symptoms of 18 insecticides on silkworm showed that different pesticides displayed similar symptoms like vomitive,distorted,"C" or "S" shaped and repose etc.While the toxicosis process of the incretion insectcides and chitin synthesis inhibitors were relatively slow.