三种淡色库蚊抗菊酯品系的生存力比较

目的 在实验条件下通过对3种拟除虫菊酯抗性品系的蚊虫选育,了解抗性发生、发展规律,为蚊、蝇的防制提供理论依据。方法 采用浸液法,分别用三氟氯氰菊酯、溴氰菊酯、胺菊酯对淡色库蚊进行抗性品系的选育,了解抗性发生、发展规律;分析抗性品系的种群生存力等主要生物学特征,比较3个品系的相对适合度。结果 胺菊酯不易产生抗性,在连续选育8代后抗性仅达4．66倍;三氟氯氰菊酯、溴氰菊酯易产生抗性。对三氟氮氰菊酯抗性经6代的选育后达到41．8倍,对溴氰菊酯抗性经5代的选育后达到50．68倍。结论 抗性品系存在相对适合度缺陷。三氟氮氰菊酪、溴氰菊酯、胺菊酯抗性品系相对适合度分别为0．41、0．47和0．29。     

淡色库蚊二氯苯醚菊酯抗性株的选育

目的：研究蚊虫对拟除虫菊酯抗性的发生发展规律，深入探讨抗性机理。方法：在实验室条件下，对淡色库蚊敏感品系用二氯苯醚菊酯丙酮液筛选，连续筛选20代。结果：成功地选育出淡色库蚊实验室抗性品系，现抗性倍数保持在70倍左右。结论：该抗性品系的种群生存力明显降低，表现为用药后卵孵化率、化蛹率、羽化率和成成蚊率比正常的敏感品系要低。     

家蝇对氯氰菊酯抗性的风险评估与预报

目的 评估家蝇(Musca domestica)对氯氰菊酯抗性风险，预测抗性发展速率。方法 采集自然种群家蝇带回室内饲养，采用点滴法用氯氰菊酯筛选抗性品系，测定LD50；采用Tabashnik的方法测定抗性遗传力和预测抗性发展速率。结果 家蝇在室内饲养并用氯氰菊酯连续筛选了10代，平均存活率54．5％，抗性上升了50倍。测得抗性遗传力h^2为0．1577。据此预测在50％～90％的杀死率的选择压力下，要获得10倍的抗性仅需2．2～4．8代。结论 家蝇对氰氰菊酯抗性上升迅速，10代内抗性遗传力基本稳定。     

药物筛选对高抗氯氟氰菊酯家蝇的抗性变化研究

目的 用溴氰菊酯、甲基嘧啶磷两种杀虫剂筛选及不接触药物自然衰退的方式，研究氯氟氰菊酯高抗性家蝇品系的变化，探讨蝇类抗药性治理的方法。方法 用喷雾法分别喷洒溴氰菊酯和甲基嘧啶磷于氯氟氰菊酯高抗药性家蝇品系（Cyh—R），进行进一步的抗性选育，分别命名为中溴（ZX）、中甲（ZJ），同时自然衰退法得到中衰（ZX）品系。用点滴法测定氯氟氰菊酯对这些家蝇品系的毒力，比较抗药性的变化。结果 与敏感品系比较，Cyh—R品系的抗药系数为561．9；氯氟氰菊酯对ZJ品系第2～6代的LD50呈递减趋势，抗药系数从F2的518．2降为F4的110．3与F6的122．6；氯氟氰菊酯对ZX品系第2～8代的LD50呈先递减再上升的趋势，抗药系数从F2的476．4降为F4的217．2，上升为F8的808．0；ZS品系的抗药系数由F0的561．9下降为F8的242．3。结论 对于氯氟氰菊酯高抗性品系家蝇，用有机磷杀虫剂后，可降低对氯氟氰菊酯的抗药性；用拟除虫菊酯筛选可造成对氯氟氰菊酯抗药性增长；不用杀虫剂筛选对氯氟氰菊酯的抗药性也有显著下降，但下降的速率低于甲基嘧啶磷筛选。     

北京市区德国小蠊对4种杀虫剂的抗性测定

目的：了解德国小蠊敏感品系（ｓ）和北京市区４个野外品系（Ｄ、Ｃ１、Ｃ２、Ｈ）对氯氰菊酯、溴氰菊酯、二氯苯醚菊酯及敌敌畏的敏感性，以便通过抗性水平来指导合理用药。方法：药膜接触法。结果：北京市区４个野外品系对上述４种杀虫剂的平均抗性系数分别为敏感品系的３．８１、２．３０、２．９４、３．１６倍；其中二氯苯醚菊酯与敌敌畏在Ｈ品系中、氯氰菊酯在Ｄ品系中均产生了较高抗性，其抗性系数分别为５．３８、６．９７和５．３１。结论：北京市区４个野外品系德国小蠊对３种常用拟除虫菊酯类药剂和１种有机磷类药剂已产生不同程度的抗性     

家蝇溴氰菊酯抗性发展规律及其交互抗性研究

目的探讨家蝇对溴氰菊酯的抗性发展规律及对常用杀虫剂的交互抗性水平,为延缓家蝇抗性的产生及制定抗性治理措施提供科学依据。方法采用室内抗性选育的方法获得抗性品系,通过生物测试法测定抗性品系对供试药剂的交互抗性。结果经过21代的室内选育,相对于实验室的敏感品系,家蝇对溴氰菊酯的抗性倍数上升2 197.55倍。家蝇对溴氰菊酯的抗性发展大体上可以分为3个阶段,前7代的抗性发展非常缓慢,从第8代开始迅速上升,筛选后期逐渐趋于平缓。家蝇溴氰菊酯抗性品系对供试杀虫剂均产生了不同程度的交互抗性。在拟除虫菊酯类杀虫剂中,家蝇产生的交互抗性顺序为高效氯氰菊酯>顺式氯氰菊酯>氯菊酯>胺菊酯>联苯菊酯,对氯氰菊酯不同异构体交互抗性明显不同,对高效氯氰菊酯交互抗性高达121.32倍。对残杀威和仲丁威的交互抗性分别为7.61和4.56倍,而对敌敌畏、毒死蜱、阿维菌素和吡虫啉交互抗性均比较低。结论长期大量使用一种杀虫剂易产生抗性,并对作用机理相同的其他杀虫剂产生交互抗性,在用药时应注意种类的选择和科学合理使用杀虫剂。     

家蝇对两种拟除虫菊酯类杀虫剂抗性的稳定性

目的 评估家蝇种群对拟除虫菊酯类杀虫剂抗性的稳定性。方法 在连续使用拟除虫菊酯类杀虫剂多年的内蒙古赤峰市屠宰场采集家蝇自然种群，带回实验室饲养并测定其对氯氰菊酯和溴氰菊酯LD50的变化情况。结果 家蝇连续用氯氰菊酯选择10代，相对抗性上升了49．96倍，LD50是敏感品系的1412．75倍。自然种群家蝇脱离用药环境后，对氯氰菊酯的抗性衰减较为缓慢，30代仍不能恢复敏感性；而对溴氰菊酯的抗性衰减不明显，至12代时仍保持223．36倍的抗性。结论 家蝇对氯氰菊酯抗性上升较快，对氯氰菊酯和溴氰菊酯抗性衰减缓慢。     

家蝇对辛硫磷抗性预测研究

目的：预测辛硫磷防治家蝇造成的抗性趋势；方法：用辛硫磷对家蝇进行室内选育，用点滴法测定家蝇的抗性水平，无选择压力下饲养观察家蝇对辛硫磷的敏感性变化，观察不同抗性水平家蝇的生物学；结果：经过8次辛硫磷处理，家蝇抗性水平RF由38上升到633，而在无选择压力下30代后，家蝇抗性水平RF从44衰迟到16。用辛硫磷处理的家蝇对胺菊酯、氯氰菊酯和氯菊酯的敏感性上升，LD50分别下降了71．7％、54．1％和45．1％，而对乙酰甲胺磷、益必添、杀螟松及溴氰菊酯敏感性下降，LD50分别上升了271．0％、105．7％、66．0％和55．0％，而5％的残杀威对家蝇的24h死亡率只有20％。低抗性水平家蝇成蝇大量发生早于高抗性水平家蝇，其蛹期内的前6d蛹量占整个世代的约50％，而高抗性水平家蝇仅占25．0％左右；结论：家蝇对辛硫磷抗性增长速度远远大于抗性衰退的速度。用辛硫磷防治家蝇时不宜连续使用，可以与辛硫磷轮用的菊酯类杀虫剂有胺菊酯、氯氰菊酯和氯菊酯。化学方法防治低抗性水平的家蝇应在种群大量发生的早期进行，而防治高抗性水平的家蝇应该采用有长期控制作用的方法。     

宁波市淡色库蚊对杀虫剂的抗药性调查及治理对策

目的：调查淡色库蚊对杀虫剂抗药性，积累抗性本底资料，以便研究治理对策。方法：微量点滴法、药膜接触法。结果：点滴法测试结果表明，淡色库蚊对胺菊酯、氯氰菊酯已产生一定抗性，分别是敏感品系的4．13和4．06倍，其后顺次为敌敌畏、高效氯氰菊酯、氯菊酯、EBT，抗性倍数分别为2．10、2．63、2．49、2．13倍，抗性不明显。对残杀威、溴氰菊酯、巴沙、三氯杀虫酯，接近敏感水平。药膜法测试结果表明，胺菊酯是敏感品系的3．01倍，产生了明显抗性，其余9种杀虫剂均接近敏感水平。结论：淡色库蚊对胺菊酯和氯氰菊酯已产生了一定的抗药性，但趋低抗水平。因此，通过控制、交替和轮换用药等抗性治理措施后，使抗性保持在低抗和敏感状态。但要加强对该地的抗性跟踪监测，密切注意抗性变化，使抗性保持在低水平状态。     

舰艇德国小蠊对氯菊酯抗性的研究

目的：开展氯菊酯对德国小蠊的抗性调查、交互抗性、抗性消退和增效研究；方法：果酱瓶药膜法；结果：8个调查点的3年抗性调查的抗性倍数为0．54-7．93，德国小蠊经氯菊酯培育后，抗性倍数由3．40增长到8．02倍需2年半，对溴氰菊酯、氯氰菊酯和残杀威的交互抗性倍数分别为2．40-4．14、1．83-4．78和1．16-1．69，抗性品系不接触杀虫剂，培育至第4代，抗性消失了37．22％，至第8代可消失69．74％，至第10代可消失85．79％，氯菊酯加入S2和S1后，对抗性品系增效倍数分别为1．22—1．48和1．45-1．96，48h死亡率均为100％；结论：部分调查点己产生抗性，抗氯菊酯品系对溴氰菊酯、氯氰菊酯己产生交互抗性，对残杀威未产生交互抗性，由中抗性转变为低抗性至基本消失，需要3年，增效剂能提高氯菊酯灭蟑螂的效果，且对氯菊酯的增效作用S1比S2强。     

Larvicidal effect of andiroba oil, Carapa guianensis (Meliaceae), against Aedes aegypti

The aim of this work was to evaluate the larvicidal effect of andiroba oil, Carapa guyanensis, against 2 strains of Aedes aegypti. After 8 h after exposure to oil, the lethal concentration (LC)90 and LC95 values for the GCZ (temephos-resistant) strain larvae were 80 and 86 ppm (1st instars), 98 and 106 (2nd instars), 166 and 182 (3rd instars), and 192 and 202 ppm (4th instars), respectively. TheLC90 and LC95 values for the Rockefeller strain larvae were 164 and 182 ppm (1st instars), 212 and 224 (2nd instars), 210 and 226 (3rd instars), and 450 and 490 ppm (4th instars), respectively. Comparison of the 2 laboratory strains of Ae. aegypti in the present study demonstrated significant variation in the susceptibility of larvae to andiroba oil. Whether a higher susceptibility of field populations of Ae. aegypti to andiroba oil occurs remains to be investigated.     

Resistance and response to selection to deltamethrin in Anopheles sinensis from Zhejiang, China

Resistance levels to deltamethrin were measured in 5 natural populations of Anopheles sinensis. The median lethal concentrations (LC50S) of deltamethrin in these populations were higher than those in susceptible strains originating from the same populations, especially in the Wenzhou population, which had a resistance ratio (RR50) of 11 relative to its susceptible strain. Resistant strains were selected with deltamethrin for 12 generations. Resistance levels in resistant strains were 130 to 190-fold higher than in susceptible strains, and 10 to 40-fold higher than in natural populations. Response of selection (R) in the resistant strain from the Wenzhou population was less than 0.1, and those in resistant strains from other natural populations were more than 0.1. This suggests that a resistant strain from a natural population with higher resistance has a lower increase in RR than a resistant strain from a natural population with low resistance under identical insecticide selection. These results are discussed in relation to mosquito control strategies.     

Larvicidal effect of Eucalyptus grandis essential oil and turpentine and their major components on Aedes aegypti larvae

In the search for new alternatives for the control of Aedes aegypti the larvicidal activity of Eucalyptus grandis essential oil and pine resin essential oil (turpentine) and their major components (alpha- and beta-pinene and 1,8-cineole) was determined. Gas chromatography-mass spectroscopy analysis of E. grandis essential oil revealed that its major components are alpha-pinene and 1,8-cineole. Similar analysis of turpentine obtained by distillation of the resin pitch of conifers showed that alpha- and beta-pinene are the only major components. Third and early 4th instars of the CIPEIN-susceptible strain of Ae. aegypti were exposed to acetonic solutions of E. grandis essential oil, turpentine, and their major components for 24 h. Turpentine, with an LC50 of 14.7 ppm, was more active than the essential oil of E. grandis (LC50: 32.4 ppm). Larvicidal activity of the essential oil components showed that alpha- and beta-pinene present low LC50 values (15.4 and 12.1 ppm, respectively), whereas pure 1,8-cineole showed an LC50 of 57.2 ppm. These results suggest that alpha-pinene in E. grandis and alpha- and beta-pinene in turpentine serve as the principal larvicidal components of both oils. Results obtained on larvicidal effects of essential oil of Eucalyptus grandis and turpentine could be considered a contribution to the search for new biodegradable larvicides of natural origin.     

Effect of sublethal concentrations of chlorpyrifos on three successive generations of Daphnia carinata

Effects of sublethal concentrations of chlorpyrifos (ranging from 0.005 (0.01 LC(50)) to 0.500 microg/L (1 LC(50))) on population characteristics of individual cultures of Daphnia carinata were investigated over 21 days with subsequent testing of the two next generations. The endpoints for the first and second generations observed were survival, fecundity, time to first brood, and number of offspring per female. The results were incorporated into the computation of the intrinsic rate of natural increase for daphnids in each of the treatments. Exposure to chlorpyrifos affected survival and fecundity of animals in the first generation. In the second generation, the most affected endpoint was time to the first brood with an indication of hormesis. The LC(50) tests were then conducted using animals of the third generation from each of the exposures in individual tests. Despite the absence of a negative effect of chlorpyrifos in the second generation, results of testing the third generation showed constant significant decline in LC(50) from control daphnids through to 0.1 LC(50) preexposed daphnids (0.1 LC(50), 0.05 microg/L, being the highest concentration in which animals survived exposure to the toxicant in the second generation).     

Continuous, mixed, and alternating exposure to deltamethrin and fenthion affect development of resistance in Culex pipiens pallens in China

A field population of Culex pipiens pallens was collected from Nanjing, China on July in 2000 and reared in an insectarium. Larvae were subjected to single, mixed, and alternating exposure to deltamethrin and/or fenthion, and the surviving early 4th instars were reared for establishment of adult colonies. Larvae from the colonies were then subjected to the same selection pressures over the subsequent 15 generations. Resistance rates and ratios were measured as LC50 values derived from larval bioassays. In populations exposed to deltamethrin or fenthion alone (single exposure), resistance levels rose rapidly. The LC50 values for deltamethrin and fenthion alone were 29.3 and 1.565 mg/liter, respectively, and the ratios of resistance were 697.6- and 24.8-fold, respectively. Exposure to a mixture of deltamethrin and fenthion (1:1; mixed selection) reduced the development of resistance. The LC50 value and ratio of resistance for the mixture of deltamethrin and fenthion were 0.607 mg/liter and 14.8-fold, respectively, at generation 15. Exposure to alternating treatments of deltamethrin and fenthion (alternating selection) showed an even lower development of resistance. For the alternating treatments, the LC50 value and ratio of resistance to deltamethrin were 0.795 mg/liter and 17.7-fold, respectively (generation 14), and those to fenthion were 0.219 mg/liter and 3.6-fold, respectively (generation 15). Together, these results indicate that the single continuous insecticide selection generated a much more severe resistance than a mixture and/or alternating treatments.     

Acute Toxicity of Agricultural Pesticides to Embryo-Larval and Juvenile African Catfish Clarias gariepinus

Acute toxicities of Tihan 175 O-TEQ, as well as its active ingredients flubendiamide and spirotetramat, and of Thionex 350 EC (active compound endosulfan) were measured for embryo-larval and juvenile stages of the African catfish Clarias gariepinus to assess risks of pesticide use in the cotton basin in Benin (West Africa). For embryo-larval stages, Tihan was more toxic (LC50_48h 20 ppm) than Thionex (LC50_48h 56 ppm), and flubendiamide was more toxic (LC50_48h 2.0 ppm) than spirotetramat (LC50_48h 8.44 ppm). All decreased hatching rates. Tihan and spirotetramat disturbed larval swimming coordination; flubendiamide induced tail cleavage. For juvenile fish, Thionex was more toxic (LC50_96h 0.22 ppm) than Tihan (LC50_96h 8.8 ppm), and flubendiamide (LC50_96h 4.7 ppm) was more toxic than spirotetramat (LC50_96h 6.0 ppm). Eggs were more resistant than juvenile fish to all tested pesticides except flubendiamide. Although Thionex was more toxic to juvenile fish, replacing Thionex with Tihan may be undesirable for survival of eggs and larvae.     

抗溴氰菊酯淡色库蚊酯酶同工酶IEF初步分析

本文采用等电聚焦法电泳（ＩＥＦ）初步比较分析了ＬＣ５０分别为０．０２４，２．５８和２１．２７ＰＰＭ的敏感品系与抗溴氰菊酯品系淡色库蚊的酯酶同工酶，结果显示各谱带没有质的区别，但在ＰＩ５．６２，ＰＩ５．８０这两条主带宽度有交叉变化现象，这提示淡色库蚊抗溴氰菊酯的抗性产生可能与基因的表达调控有密切关系，这可为今后研究蚊虫抗性的产生机理提供有价值的参考。     

Acute inhalation toxicology of nitrogen trichloride

The LC50 of nitrogen trichloride (NCl3) was determined in rats following a one hour inhalation exposure. Five groups of 10 animals per group were exposed to a concentration range of NCl3 from 58 ppm to 157 ppm. The one hour LC50 is 112 ppm with the 95% confidence interval between 107 ppm and 117 ppm. All mortality occurred during or within one day following the exposure. Gross necropsy of the animals which died as a result of exposure to NCl3 showed noticeable fluid in the trachea and lungs. This was not the case for those animals which survived the exposure (gross necropsies performed 14 days post-exposure). Pulmonary edema appears to contribute significantly to mortality produced by NCl3.     

Toxicity of 19 adjuvants to juvenile Lepomis macrochirus (bluegill sunfish)

Nineteen adjuvants, many used as surfactants for aquatic herbicide applications, were applied in static bioassay to bluegill sunfish (Lepomis macrochirus) for 96 h to determine median lethal concentrations (LC50). Surfactants are added to the tank mix as a percentage (v/v) of the total volume, in contrast to herbicide application rates, which are usually expressed in kilograms per hectare. Two ethoxylated tallow amine products were the most toxic, having LC50 values of 1.6 and 2.9 ppm (all values v/v). Seven alcohol/glycol-based surfactants had 96-h LC50 values of 4.0 to 11.6 ppm (mean = 7.9 ppm). The polysiloxane- or silicone-based surfactants had toxicities of 18.1 to 29.7 ppm (mean = 24.7). Two limonene-based products had LC50 values of 10.2 and 30.2 ppm. A methylated seed oil with emulsifier had a LC50 of 53.1 ppm. Two acid/buffer utility adjuvants had LC50 values of 60.8 and 221 ppm. To compare the relative safety of the tested surfactants, we assumed maximum label rate applications to 1 m deep water with uniform mixing. This comparison of relative safety is based on mortality to 50% of the test organisms and does not imply application rates that would not result in any mortality. The two ethoxylated tallow amines, neither used or recommended for aquatic applications, had a relative safety factor of 12.6 or less. Relative safety factor varied from 6.2 to 20.4 for the seven alcohol/glycol surfactants, 38.4 to 63.2 for silicone-based products, 5.5 to 16.1 for limonene products, 113 for methylated seed oil, and 132.2 to 315.7 for acid/buffer utility adjuvants. When used according to label recommendations under normal use conditions, these adjuvants should not be present in acutely toxic concentrations; however, the most toxic adjuvants in very shallow water (< 10 cm) would be toxic to bluegill sunfish that did not move to deeper water to avoid lethal concentrations.