3类杀虫液抑蚊效果研究

探求3种不同杀虫剂对2种品系白蚊伊蚊的致死效果,并对其抗性进行对比研究。在(26.3±1.0)℃,相对湿度(65.0±10.0)%的条件下,采用浸渍法测定了高效氯氰菊酯、敌敌畏、残杀威分别对敏感、野生品系白纹伊蚊24 h内的半数致死浓度LC_(50)及其抗性倍数。高效氯氰菊酯对敏感品系和野外品系的白纹伊蚊24 h内的半数致死浓度分别为0.0073 mg/L和0.0189 mg/L;敌敌畏对敏感品系和野生品系的白蚊伊蚊24 h内半数致死浓度LC_(50)分别为0.2062 mg/L和0.5115 mg/L,残杀威对野外和敏感品系和野生品系的白蚊伊蚊LC_(50)分别为3.5987 mg/L和1.6796 mg/L。在抗性测定试验中,残杀威抗性倍数为2.1,相对另外2种药物,其抗性倍数最低,高效氯氰菊酯和敌敌畏分别为2.6和2.5,综合考虑致死效果及积累因素,3种药物都为低抗性药物,高效氯氰菊酯的致死效果最好,残杀危的抗性最小。     

84种植物光活化杀虫活性的筛选

以白纹伊蚊4龄幼虫为试虫,在近紫外光照射条件下测试了采自广西和甘肃的84种植物甲醇粗提物的杀虫活性。结果表明,我国特有植物黄缨菊具有光活化杀虫活性,经500μg/mL粗提物处理的试虫,光照组在光照结束后24 h的校正死亡率达到100%,而避光组仍无死亡。黄缨菊根、花、叶的活性依次递减,经500μg/mL根、花和叶粗提物处理的试虫,光照组在光照结束后24 h的校正死亡率分别为100%、45.56%和16.67%,而避光组无死亡,表明黄缨菊的杀虫活性成分主要存在于根中。     

Paradoxical effects of sublethal exposure to the naturally derived insecticide spinosad in the dengue vector mosquito,Aedes aegypti

BACKGROUND: Recent studies have indicated that spinosad, a mixture of two tetracyclic macrolide compounds produced during the fermentation of a soil actinomycete, may be suitable for controlling a number of medically important mosquito species, including the dengue vector, Aedes aegypti L. The authors determined the effects of a 1 h exposure to a 50% lethal concentration (LC₅₀) of spinosad in the larval stage on the wing length, longevity and reproductive capacity of the adult survivors. RESULTS: The LC₅₀ of spinosad for a wild‐caught population of Ae. aegypti from Chiapas, southern Mexico, was estimated to be 0.06 mg AI L^?1 in late third instars. Paradoxically, the female survivors of exposure to this concentration were significantly larger (as determined by wing length) laid more eggs, but were slightly less fertile than control females. This was probably due to elimination of the smaller and more susceptible fraction of mosquito larvae from the experimental population following spinosad treatment. Male survivors, in contrast, were significantly smaller than controls. No significant differences were detected in the adult longevity of treated and control insects of either sex. CONCLUSIONS: The increase in reproductive capacity of spinosad‐treated females did not compensate for mortality in the larval stage and would be unlikely to result in population increase in this mosquito under the conditions that were employed. Sustained‐release formulations would likely assist in minimizing the occurrence of sublethal concentrations of this naturally derived product in mosquito breeding sites. Copyright © 2008 Society of Chemical Industry     

Thermal behaviour and biological activity against Aedes aegypti (Diptera: Culicidae) of permethrin and pyriproxyfen in a smoke‐generating formulation

BACKGROUND: The most common ways to control dengue vector Aedes aegypti (L.) are larval source reduction in domestic habitats and ground application of small quantities of aerosol insecticide (ultralow volume). Nevertheless, these actions have been shown repeatedly to be ineffective in controlling Ae. aegypti populations. RESULTS: The efficacy of a new smoke‐generating formulation containing pyriproxyfen and permethrin was evaluated in the laboratory. Smoke‐generating tablets containing each insecticide individually or combined were prepared, and the recovery of the insecticides from the smoke was determined. Recovery values of over 90% were obtained for pyriproxyfen, and around 50% for permethrin. The biological efficacy of pyriproxyfen released in the smoke was evaluated in the laboratory, on late third‐instar or early fourth‐instar Ae. aegypti larvae, using different concentrations of pyriproxyfen and exposure times. Adult emergence inhibition (EI) values of 100% were obtained at 30 min, and a dose‐dependent effect was observed at 5 min. The effect of pyriproxyfen released in the smoke was due to direct contact with the larvicide in the water rather than by inhalation of the fumes. The efficacy of permethrin released in the fumes was also evaluated as knockdown effect (KT₅₀) on adults for a tablet containing permethrin alone or permethrin plus pyriproxyfen. There was no significant difference in KT₅₀ values obtained for permethrin (KT₅₀ = 19.9 min) and permethrin plus pyriproxyfen (KT₅₀ = 19.4 min). CONCLUSION: The excellent laboratory performance of this new formulation on immature stages and adults indicates that a smoke‐generating tablet containing pyriproxyfen and permethrin could be a new tool for controlling mosquitoes. Copyright © 2009 Society of Chemical Industry     

苦杏仁精油对白纹伊蚊的驱避活性研究

采用个体涂肤有效保护时间试验研究了苦杏仁精油对白纹伊蚊的驱避活性。结果表明,含HCN和去除HCN的苦杏仁精油对白纹伊蚊都具有很强的驱避活性,涂药8h后,2种苦杏仁精油对白纹伊蚊的驱避率均在96.76%以上,作为对照的隆力奇花露水的驱避率为58.28%。另外,2种精油对人体的有效保护时间分别为6h和7h,高于隆力奇花露水4h。可见苦杏仁精油对白纹伊蚊具有很强的驱避效果,且其有效保护时间高于隆力奇花露水,因而有望开发成为新型的蚊虫驱避剂。     

两种挥发性拟除虫菊酯杀虫剂对伊蚊的驱避作用研究

拟除虫菊酯杀虫剂广泛应用于蚊香及其他驱蚊产品,不仅对蚊子有杀虫作用,而且具有驱避效应,然而拟除虫菊酯杀虫剂对蚊子驱避作用的机理尚不清楚.本研究发现两种挥发性拟除虫菊酯杀虫剂四氟甲醚菊酯和氯氟醚菊酯对白纹伊蚊和埃及伊蚊具有非接触驱避作用.触角电位(EAG)试验表明除四氟甲醚菊酯有微弱EAG响应外,其他拟除虫菊酯杀虫剂均没...     

Effect of rotenoids from the seeds of Millettia dura on larvae of Aedes aegypti

A crude chloroform extract of seeds of Millettia dura Dunn (Leguminosae) showed high activity (LC50 = 3.5 microg ml(-1) at 24 h) against second-instar larvae of the mosquito, Aedes aegypti L (Diptera: Culicidae). The rotenoids, deguelin and tephrosin, isolated from the seeds of this plant also showed potent activities, with LC50 values of 1.6 and 1.4 microg ml(-1) at 24 h, respectively. The related rotenoids millettone and millettosin were inactive at 20 microg ml(-1). Saturation at the B/C ring junction and the presence of methoxy groups at C-2 and/or C-3 in deguelin and tephrosin appear to be important for the observed larvicidal activity.     

两种罗索线虫对不同蚊种的自然感染及实验研究

1984年在河南信阳地区发现两种蚊体寄生索线虫,在同一孳生地内生长繁殖,分别寄生于中华按蚊和致倦库蚊及三带喙库蚊等幼虫体内,自然寄生率为5.48％、4.32％、5.82％。通过人工感染试验,感染率均较高,可达61.5％～95.7％。试验证明两者对按蚊和库蚊具有显然不同的生理特性。这两种罗索线虫在稻田、田沟等多种水体内均有孳生,宿主范围广泛,有应用价值。