拟除虫菊酯开发新热点

1前言 拟除虫菊酯是一类重要的仿生性杀虫剂,20世纪70年代初英国Elliott发现光稳定性拟除虫菊酯后,在农业上得以推广应用,它们的开发是继有机氯杀虫剂、有机磷杀虫剂、氨基甲酸酯杀虫剂之后的一个新突破,是杀虫剂历史上的第三个里程碑.     

拟除虫菊酯混配水基杀虫制剂现场杀虫效果观察

本文报道拟除虫菊酯混配水基杀虫制剂现场杀虫试验结果。以1ppm剂量处理污水池,对蚊幼杀灭率为92.1%;5ml/m~3剂量,对淡色库蚊成虫16分钟击倒率为88.5%,24小时死亡率为100%:此剂量对家蝇的杀灭率为98～100%,还可有效地控制德国小蠊的危害。由此可见,它是一种高效广谱卫生杀虫制剂,可广泛用于列车、家庭及公共场所。     

拟除虫菊酯水剂杀虫剂的研制

选择合适的助溶活性剂和拟除虫菊酯配制而成的水剂杀虫剂，经实验室和现场试验，对蚊蝇、蟑螂都有显著杀灭作用，并且有高效、低毒、稳定性好和价格低廉等优点，对卫生害虫的击倒、杀灭作用优于同等含药量的醇制剂，目前已经应用于部队。     

钠离子通道与拟除虫菊酯击倒抗性的研究进展

拟除虫菊酯类杀虫剂具有高效低毒低残留性 ,现已占有全球超过 2 5 %的杀虫剂市场 ,广泛用于农业和卫生害虫的防制。然而 2 0多年来的持续应用 ,导致很多昆虫都对之产生了抗药性 ,从而减损了这种杀虫剂持续有效的应用〔1〕。神经生理学研究表明 ,ＤＤＴ和拟除虫菊酯的作用机制是干扰电位依赖的Ｎａ 通道闸门开闭的动力学 ,使得Ｎａ 通道延迟关闭 ,引起重复后放 (ｒｅｐｅｔｉｔｉｖｅａｆｔｅｒｄｉｓｃｈａｒｇｅ)和突触传递的阻断〔2 -3〕。昆虫神经系统对拟除虫菊酯类杀虫剂的敏感性下降主要与神经细胞膜上Ｎａ 通道的敏感性降低有关。…     

鱼体内拟除虫菊酯农药的检出

2010年12月,我们收到养鱼场一份死鱼样本和2份水样,进行毒物检测。取数块硅胶G商品板,烘箱中110度加热1 h,放入干燥器。水样各取50 ml于60 ml分液漏斗中,每次加10 ml三氯甲烷,萃取3次,萃取液加少许无水硫酸钠脱水,置于蒸发皿中50℃以下水浴浓缩近干。     

Occupational exposure to organophosphorus insecticides and synthetic pyrethroid

Summary Dermal and respiratory exposure to pirimiphosmethyl, dimethoate and permethrin were determined for applicators and operators in greenhouse tomato spraying operations. Dermal exposure is several times higher than the degree of respiratory exposure. Dermal exposure in terms of different parts of the body shows significant differences. For applicators the exposure of hands, arms and legs is the greatest, and the operators are the most exposed on their hands and to a small extent on legs. This fact should be taken into account when providing the workers with suitable protective clothing. The carefully selected technology of spraying also has great significance in decreasing the degree of exposure. Because of the chronic toxicity of dimethoate, all possible methods should be taken to reduce exposure.     

Enantioselectivity in aquatic toxicity of synthetic pyrethroid insecticide fenvalerate

Synthetic pyrethroids (SPs) are a family of chiral insecticides with a large number of stereoisomers. Fenvalerate (FV) is one of the most potent pyrethroid insecticides, controlling a wide range of insect pests in agricultural fields, public health situations and animal houses. FV contains two chiral centers. In this study, four stereoisomers of FV were absolutely separated by high-performance liquid chromatography with a commercial chiral column, CHIRALCEL^® OJ-H, using n-hexane containing 1,2-dichloroethane and ethanol as mobile phase. Toxicity assays of each isomer and racemate of FV were performed using Daphnia magna (D. magna), zebrafish (Danio rerio) and zebrafish embryo-larval. In the acute toxicity of D. magna, significant differences were observed: the 24 h EC₅₀ of αS-2S-FV was 51 times more toxic than the αR-2R-FV, and the 48 h LC₅₀ results showed that the αS-2S-FV was 99 times more toxic than αR-2R-FV. In the toxicity assay of D. rerio, dramatic differences were also found: the LC₅₀ value of αS-2S-FV was 17, 22, 39 and 56 times more toxic than the αR-2R-FV at 24, 48, 72 and 96 h, respectively. The assays of 4-day-old zebrafish embryo-larval showed that the exposure to FV enantioselectively induced crooked body, yolk sac edema and pericardial edema and that the αS-2S-FV was 3.8 times stronger than the other isomers in 96-h mortality. The results indicate that the enantiomeric differences should be taken into consideration in assessing the ecological effects of SPs.     

Desirability of three synthetic pyrethroid aerosols for aircraft disinsection

Of several aerosol formulations of 3 synthetic pyrethroids, S-2539 Forte, resmethrin, and bioresmethrin, the 2% formulation was most effective for the disinsection of passenger spaces aboard jet aircraft; the 1.2% and 0.3% formulations were less effective. Break-off tip aerosol units gave good dispersal, but these limited production cans showed slight variability in the rate of release.     

Variation in cutaneous perfusion due to synthetic pyrethroid exposure

Synthetic pyrethroids are neurotoxic insecticides with a low mammalian toxicity. Prior investigations have found these agents to be neither cutaneous irritants nor sensitisers. Clinically demonstrable inflammation, as judged by erythema, oedema, or vesiculation, has not been apparent. Nevertheless, paraesthesia does result from cutaneous exposure. In this investigation technical grade flucythrinate was applied to the forearms of human participants twice daily for five consecutive days. Laser Doppler velocimeter measurements were made before each topical application, with histamine phosphate being intradermally injected on termination of the study. Results of both laser Doppler velocimetry and histamine induced axon reflex vasodilatation were not statistically significant at an alpha = 0.05 level. This investigation suggests that the synthetic pyrethroids have little influence on neurogenic vasodilatation on topical exposure.     

Variation in cutaneous perfusion due to synthetic pyrethroid exposure.

Synthetic pyrethroids are neurotoxic insecticides with a low mammalian toxicity. Prior investigations have found these agents to be neither cutaneous irritants nor sensitisers. Clinically demonstrable inflammation, as judged by erythema, oedema, or vesiculation, has not been apparent. Nevertheless, paraesthesia does result from cutaneous exposure. In this investigation technical grade flucythrinate was applied to the forearms of human participants twice daily for five consecutive days. Laser Doppler velocimeter measurements were made before each topical application, with histamine phosphate being intradermally injected on termination of the study. Results of both laser Doppler velocimetry and histamine induced axon reflex vasodilatation were not statistically significant at an alpha = 0.05 level. This investigation suggests that the synthetic pyrethroids have little influence on neurogenic vasodilatation on topical exposure.     

ETOC and lambdacyhalothrin: new pyrethroid mosquito adulticides

Two new pyrethroids, ETOC and lambdacyhalothrin, showed considerable promise against organophosphorus-resistant adults of Culex tarsalis in laboratory tests. In field trials using nonthermal aerosols, applications of both compounds resulted in effective swaths of up to one-half mile. At the highest concentrations evaluated, residues on alfalfa foliage were less than 0.2 ppm at 1 h. Residues declined greatly by 24 h and could not be detected at 48 or 72 h.