丁烯氟虫腈对家蚕(Bombyx mori)的急性毒性与风险评价

采用食下毒叶法、药膜法和点滴法测定丁烯氟虫腈对家蚕的急性毒性,并进行了急性风险评价。食下毒叶法结果表明丁烯氟虫腈对蚁蚕、2龄、3龄、4龄和5龄起蚕的摄入LC50值(96h,下同)分别为280(227～343)、578(507～652)、3612(3178～4139)、6790(6045～7875)、7151(5932～8705)mg·L-1,均大于200mg·L-1,属于低毒级;桑叶浸药时间为1s、10s、1min、10min和60min时,丁烯氟虫腈对2龄起蚕的LC50值分别为789(690～913)、578(507～652)、443(382～499)、396(349～447)、254(222～285)mg·L-1;家蚕在丁烯氟虫腈药膜上爬行10、30和60min后,对2龄起蚕的接触LC50值分别为101(86.8～131)、66.7(61.7～74.1)、60.9(51.0～83.4)μg·cm-2,对3龄起蚕的点滴接触LD50值为76.2(70.2～84.9)μg·larva-1。急性风险评价结果表明,丁烯氟虫腈对蚁蚕具有中等风险性,对其他龄期家蚕为低风险。因此,丁烯氟虫腈对家蚕的急性毒性和急性风险均较低。

Acute Toxicity and Risk Assessment of Butene-fipronil to Silkworm, Bombyx mori

Acute toxicities of butene-fipronil to silkworm (Bombyx mori) in different situations were evaluated by the methods of feeding toxic mulberry leaves, methods of topical application on the pronotum and contacting with toxic membrane, respectively. And the risk assessment for butene-fipronil was also made. For the first, second, third, fourth and fifth-instar larvae, the 96 h-LC50 values of butene-fipronil to silkworm were 280 (227-343), 578 (507-652), 3612 (3178-4139), 6790 (6045-7875), 7151 (5932-8705) mg·L-1, respectively, which were higher than 200 mg·L-1, belonging to low-level toxicity. When immersion time of mulberry leaves in butene-fipronil solution was 1 s, 10 s, 1 min, 10 min and 60 min, the 96 h-LC50 values to the second-instar larvae were 789 (690-913), 578 (507-652), 443 (382-499), 396 (349-447), 254 (222-285) mg·L-1, respectively. After 10, 30 and 60 min contact of silkworm with filter paper treated by butene-fipronil solution, the 96 h-LC50 values to the second-instar larvae were 101 (86.8-131), 66.7 (61.7-74.1), 60.9 (51.0-83.4) μg·cm-2, respectively. The 96 h-LD50 value by topical application on the pronotum to the third-instar larvae was 76.2 (70.2-84.9) μg·larva-1. The acute risk assessment results showed that the acute risk of butene-fipronil to the first-instar larvae was intermediate and those of butene-fipronil to other instar larvae were low. It is indicated that the acute toxicity and risk of butene-fipronil to silkworm are both low.