杀虫剂轮用和混用对害虫种群抗性演化的影响

杀虫剂轮用和混用是当前害虫抗药性治理中最常采用的两种用药策略。该文用抗性模型和室内试验对轮用和混用延缓害虫抗性演化的效果及轮用最佳间隔期问题作了研究。模型模拟结果表明,在延缓害虫抗性演化方面轮用和混用对抗性演化的影响主要取决于杀虫剂作用强度、抗性基因型个体的适合度大小和杀虫剂混用后的毒理效应类型。两种杀虫剂轮用时,轮用间隔期以1(即两种杀虫剂隔次施用)为佳。以模型昆虫小菜蛾Plutella xylostella在室内试验结果表明,氰戊菊酯单用(I)及与杀虫单轮用(II)和混用(1∶1)(III)连续处理8代后,抗性个体频率为0.01的小菜蛾种群其3龄幼虫对氰戊菊酯的抗性分别上升了75.87(I)、28.67(II)和58.72(III)倍,与模型模拟结果表现出较好的一致性。据此,作者认为抗性模型可用于预测害虫抗性演化和评价抗性治理策略。     

昆虫抗药性的治理策略:一个数学模型的提出

本文用计算机模型分析及评价了昆虫抗药性的三种治理策略:顺序轮用,“高杀死”策略及棋盘式用药.假设昆虫具有一定的生物学特性:如抗性为单基因,单抗性,抗性基因为半显性,两性生殖,昆虫有扩散习性,感性系在不施药情况下有微弱的适应优势等.分析了用不同剂量造成的不同的死亡率,不同的反选择作用,不同的基因稀释作用等情况对三个策略的影响.结果显示出,在这些情况下,用3—5种杀虫剂隔代顺序轮用加上微弱的反选择作用是最为有效的.“高杀死”策略加上一定的稀释作用也极为有效.棋盘式用药在特殊情况下才有用.     

溴氰菊酯家蝇在不同用药方式下的敏感性变化及其机制

以具有极高抗水平的抗溴氰菊酯家蝇Musca domestica vicina Macquart DR0品系为试虫,模拟田间几种常见的用药方式(混用、轮用、使用增效剂),在室内进行平行汰选,并以不用药和继续用原药汰选的为比较,研究试虫在这几种用药方式下的敏感性变化及其变化机制。抗性家蝇用辛溴混剂、辛硫磷以及溴氰菊酯＋SV     

朱砂叶螨不同抗性品系酯酶同工酶研究

在室内模拟田间药剂的选择压力,用3种不同药剂及其组合(轮用和混用)对朱砂叶螨Tetranychus cinnabarinus 进行抗药性选育.经过40余代的筛选,朱砂叶螨对甲氰菊酯、阿维菌素和哒螨·阿维混剂分别产生了68.5、8.7和6.7倍的抗性;甲氰菊酯和阿维菌素混用和轮用分别对甲氰菊酯产生了5.6倍和28.7倍抗性.朱砂叶螨各品系酯酶同工酶电泳结果和同工酶谱谱带密度扫描表明,与敏感品系相比,各抗性筛选品系的酯酶活性均有不同程度增加;阿维菌素抗性品系活性最强,酯酶带迁移距离明显远于其他抗性品系,表明该品系酯酶体系中存在变构酯酶.     

甲氰菊酯与阿维菌素单用、轮用和混用对朱砂叶螨抗性进化的影响

应用数量遗传学的方法分析朱砂叶螨(Tetranychus cinnabarinus)实验种群对甲氰菊酯、阿维菌素及其混剂甲氰—阿维(甲氰菊酯:阿维菌素=8.9:0.1,m/m)的抗性现实遗传力,并测定了甲氰菊酯、阿维菌素分别连续单用、轮换使用、混合使用对朱砂叶螨抗性进化的影响。结果表明,筛选16代后,朱砂叶螨对甲氰菊酯、阿维菌素和甲氰—阿维的抗性现实遗传力分别为0.2853、0.1695和0.0804,朱砂叶螨对混剂的抗性现实遗传力低于对2个单剂的遗传力的一半,混用延缓抗性的效果将好于轮用。药剂连续单用、轮换使用和混合使用16代,朱砂叶螨对甲氰菊酯的抗性分别为28.52、28.03和10.81倍,对阿维菌素的抗性分别为3.24、2.82和1.41倍。朱砂叶螨对2种杀螨剂抗性进化速率为单用>轮用>混用,抗性测定结果表明甲氰菊酯与阿维菌素混用能有效延缓朱砂叶螨对2种药剂抗性的发展速率。     

华北棉区主要害虫抗药性监测与治理技术示范

【目的】华北地区转基因Bt棉大面积种植后,刺吸式口器害虫已成为棉花主要害虫。本研究旨在监测明确棉花主要害虫对田间常用杀虫剂抗性水平变化,以指导田间合理用药。【方法】2013-2015年分别采用叶片药膜法和点滴法系统监测了河北省邱县、山东省滨州市、河南省西华县棉铃虫Helicoverpa armigera、棉蚜Aphis gossypii、绿盲蝽Apolygus lucorum对常用杀虫药剂的抗性动态变化情况。【结果】棉铃虫对辛硫磷、高效氯氟氰菊酯抗性呈上升趋势,抗性倍数都在20倍以上,对甲氨基阿维菌素苯甲酸盐从敏感状态转为中等水平抗性,抗性倍数在10倍以上。棉蚜对杀虫剂抗性水平都比较高,特别是对氧化乐果、高效氯氰菊酯、吡虫啉都已产生了高水平抗性,抗性倍数都在100倍以上。绿盲蝽对吡虫啉从敏感状态转为中等水平抗性,抗性倍数在10倍以上,对马拉硫磷、灭多威等药剂抗性倍数还维持在10倍以下,对高效氯氟氰菊酯只监测到滨州种群产生了中等水平的抗性,抗性倍数达到了95倍。在明确棉花害虫抗药性水平的基础上,对山东滨州棉花害虫实施了以轮换用药为主的抗性治理示范,示范区比农户自防对照区减少3次用药,增加棉花产量7.53%,节本增收109.16元,取得了较好的示范效果和经济效益。【结论】当前华北棉区主要害虫抗性水平上升,急需开展以轮换用药为主的抗性治理措施。     

杀虫剂混用的毒力测定

<正> 杀虫剂的合理混用不但能提高防治效果,而且是防治抗性害虫的有效手段之一。特别是增效作用的研究,在某些情况下,还可以为我们进一步了解杀虫剂的毒理作用提供线索。 Biss早在1939年就指出,杀虫剂混合时可以出现以下几种情况: (一)相似的联合作用(similar joint action)指二种毒理作用相似的杀虫剂混用,因其作用相似可作用于同一生理部位(如DDT和DDD,艾氏剂与狄氏剂等),因此一种杀虫剂的量若用适量的另一种杀虫剂来代替,可以获得同样的结果。     

抗溴氰菊酯家蝇在不同用药方式下的敏感性变化及其机制

以具有极高抗水平的抗溴氰菊酯家蝇Musca domestica vicina Macquart DR0品系为试虫,模拟田间几种常见的用药方式(混用、轮用、使用增效剂),在室内进行平行汰选,并以不用药和继续用原药汰选的为比较,研究试虫在这几种用药方式下的敏感性变化及其变化机制。抗性家蝇用辛溴混剂、辛硫磷以及溴氰菊酯＋SV₁汰选后,在F₁₆(F₁₇)代以前,对溴氰菊酯及汰选药剂的抗性发展相对都比较缓慢;F₁₆(F₁₇)代以后,用溴氰菊酯＋SV₁汰选的家蝇对溴氰菊酯的敏感性迅速下降,抗性发展很快。家蝇对溴氰菊酯的敏感性变化与药剂中溴氰菊酯的选择压有关。生化分析结果表明,在不同用药方式汰选下,家蝇体内酯酶、多功能氧化酶、谷胱甘肽-S-转移酶、乙酰胆碱酯酶的酶活或特性发生了不同的变化。     

毒杀芬的性质及其混用后的增效作用

<正> 毒杀芬是以松节油为主要原料而合成的氯化莰烯混合物。早在五十年代,我国就在浙江、福建、广东等省设厂生产,主要防治棉虫、地下害虫、玉米螟、飞虱、稻苞虫及畜牧害虫。由于在一般情况下,毒杀芬的杀虫效力不如DDT与666,因而销售量逐年下降,产品年有积压。但近年来,不少害虫对DDT与666已发生抗性,实践证明如用毒杀芬与DDT等混用,有显著增效作用。兹将毒杀芬的有效成分及混用后的增效情况介绍如下:     

广东稻区褐飞虱对烯啶虫胺和呋虫胺的敏感性测定

为了科学用药和抗性治理提供理论依据,在室内采用稻茎浸渍法测定了采自广东省广州、南雄、雷州、连州、海丰、怀集和大埔等7个地方田间褐飞虱种群对烯啶虫胺、呋虫胺的敏感性。试验结果表明:广东地区褐飞虱种群对烯啶虫胺的敏感性LC_(50)值为2.3187-7.1489mg/L,抗性倍数分别为4.93-15.21倍,南雄地区褐飞虱种群对烯啶虫胺仍处于敏感阶段;广州、海丰和雷州等3个地区褐飞虱对烯啶虫胺已产生低水平抗性,大埔、连州和怀集等3个地方褐飞虱已对烯啶虫胺产生中等水平抗性。广东地区褐飞虱种群对呋虫胺的敏感性LC_(50)值为3.6696-11.8093 mg/L,抗性倍数为26.21-84.35倍,表明广东省不同地区褐飞虱种群对呋虫胺均产生中等水平抗性。建议在防治褐飞虱时,对于低水平抗性的烯啶虫胺应轮用、混用,对中等水平抗性的呋虫胺应限制使用。     

Evolution of Resistance in the Presence of Two Insecticides

A two-locus model is used to analyze the effectiveness of a mixture of insecticides in delaying resistance, compared to the use of the insecticides singly. The effects of factors such as recombination, effective dominance, initial value of allele frequencies and initial value of linkage disequilibrium are considered. It is shown that the use of mixtures is always more effective in delaying the onset of resistance, often by many orders of magnitude. It is shown that there exists a threshold value of recombination fraction, above which the evolution of resistance is extremely slow. Resistance evolves very rapidly for values of recombination fraction below the threshold. Finally, the relevance of these results on resistance management is discussed.     

Are there effective resistance management strategies for vectors of human disease?*

The rotation of insecticides used by the Onchocerciasis Control Programme in West Africa is reviewed and the motives for this rotation are shown to be not only management of temephos resistance in the Simulium vectors but also constraints on what compounds are usable at particular seasons. A computer model indicates that without these seasonal constraints there is unlikely to be an advantage in a pre-planned rotation of insecticides, as compared with the prompt switching of compounds as dictated by detection of build up of resistance and switching back to the original compound if the regression of resistance is found to give the opportunity to do so. The latter sequence of events can hardly be called a ‘strategy’ for resistance management, but is what any well-managed pest control programme would be expected to do. The use of an insecticide mixture is different in principle from the use of rotation and depends on the idea that if the mixture is used from the outset, when resistance to both components of the mixture is likely to be rare, the double resistance combination would be so rare as to be dwarfed in numbers by those insects which avoid exposure altogether. The prospects for successful use of a mixture depend on each component killing a very high percentage of the exposed insects which are genetically susceptible to it. Whether this condition is met could be tested, for example, in the case of exposure of mosquitoes to insecticide-treated bednets.     

菜缢管蚜、棉铃虫对杀虫混剂及其单剂的抗性遗传力分析

采用阈性状分析法,估算了菜缢管蚜Lipaphis erysimi(Kaltenbach)和棉铃虫Helicoverpa armigera(Hubuer)对菊马混剂及其单剂、棉铃虫对灭铃威混剂及其单剂的抗性现实遗传力,并对抗性风险和混剂延缓抗性的作用进行了评估。结果表明,菜缢管蚜和棉铃虫对混剂的现实抗性遗传力均明显小于各单剂,依次为：拟除虫菊酯>氨基甲酸酯>有机磷>混剂。混剂的使用寿命大于组成其各个单剂的使用寿命之和,抗性风险依次为：拟除虫菊脂>氨基甲酸酯>有机磷>混剂。菊马混剂对菜缢管蚜和棉铃虫,灭铃威混剂对棉铃虫均有延缓抗性发展的作用。灭铃威对棉铃虫抗性发展的延缓作用最显著。     

镶嵌式交替防治对菜蚜抗性演化的影响

鉴于镶嵌式防治不适用于营孤雌生殖的菜蚜乇翅成蚜,于是作者对镶嵌式防治在时空上稍作微细的改变,即先以作用机理不同的杀虫剂A和B在不同区域作镶嵌式的喷洒,而后在下一次作交替防治,这相当于邻近区域间存活个体的互相迁飞。我们称此法为镶嵌式交替防治。在上海梅陇地区,自1985年以来使用这一策略防治菜缢管蚜(Lipaphis erysimi pseudobrassicae)、桃蚜(Myzus persicae)和柳二尾蚜(Cavariella salicicola)根据生物测定和单个蚜虫的醋酶活性测定,在分别与连续使用乐果直至无效,然后改用氰戊菊酯防治的菜蚜种群比较时,所得结果表明,乐果和氰戊菊酯的镶嵌式防治能延缓这些菜蚜抗性的产生。     

Efficacy of mosquito nets treated with a pyrethroid-organophosphorous mixture against Kdr- and Kdr+ malaria vectors (Anopheles gambiae)

In order to prevent the resistance of Anopheles gambiae s.l. to pyrethroids from spreading too quickly and to lengthen the effectiveness of insecticide impregnated mosquito nets, it has recently been suggested to use mixtures of insecticides that have different modes of action. This study presents the results obtained with tulle mosquito nets treated with bifenthrin (a pyrethroid) and chlorpyrifos-methyl (an organophosphorous) both separately and in mixture on two strains of An. gambiae, one sensitive to all insecticides, and the other resistant to pyrethroids. The values of KDt50 and KDt95 and the mortality induced with the mixture of bifenthrin (25 mg/m2) and chlorpyrifos-methyl (4.5 mg/m2) show a significant synergistic effect on the strain of An. gambiae susceptible to insecticides. However, the tested combination does not induce any synergistic effect on the VKPR strain selected with permethrin, but only enhances the effectiveness of the two insecticides taken separately.     

Assessment of esterase gene expression as a risk marker for insecticide resistance in Florida Culex nigripalpus (Diptera: Culicidae)

Esterases are enzymatic proteins known to play a role in insecticide resistance formation. To further our understanding of the development of insecticide resistance, we tested the gene expression level of a gene implicated in insecticide resistance (Temsha est‐1) from Culex nigripalpus Theobald (Diptera: Culicidae) in field mosquitoes. We found that the level of expression of TE‐1 differed depending on the frequency of exposure to organophosphate insecticide through expression studies. Temsha est‐1 cDNA is 1,808 base pairs and fully sequenced with up to 96% nucleotide sequence identity to esterase B genes of other mosquito species. The genes from five different species, including TE‐1, were closely related by genetic distance and phylogenetic analysis. Differential expression of this gene that is correlated to differences in susceptibility towards organophosphate would provide the ability to use Temsha est‐1 as an indicator of the formation of tolerance/resistance. This would greatly enhance mosquito control efforts by allowing targeted application of insecticides to mosquito populations that are most susceptible. Also, it would provide resistance information so that a rational design could be used for insecticide rotation schedules.     

Influence of permethrin, diazinon and ivermectin treatments on insecticide resistance in the horn fly (Diptera: Muscidae)

The history of insecticide resistance in the horn fly, Haematobia irritans, and the relationship between the characteristics of horn fly biology and insecticide use on resistance development is discussed. Colonies of susceptible horn flies were selected for resistance with six insecticide treatment regimens: continuous single use of permethrin, diazinon and ivermectin: permethrin-diazinon (1:2) mixture; and permethrin-diazinon and permethrin-ivermectin rotation (4-month cycle). Under laboratory conditions, resistance developed during generations 21, 31 and 30 to permethrin, diazinon and ivermectin, respectively. The magnitude of resistance ranged from < 3-fold with ivermectin to 1470-fold with permethrin. Field studies demonstrated that use of a single class of insecticidal ear tag during the horn-fly season resulted in product failure within 3-4 years for pyrethroids and organophosphates, respectively. In laboratory studies, use of alternating insecticides or a mixture of insecticides delayed the onset of resistance for up to 12 generations and reduced the magnitude of pyrethroid resistance. In field studies, yearly alternated use of pyrethroids and organophosphates did not slow or reverse pyrethroid resistance (Barros et al., unpublished data), while a 2-year alternated use with organophosphates resulted in partial reversion of pyrethroid resistance. When pyrethroid and organophosphate ear tags were used in a mosaic strategy at two different locations, efficacy of products did not change during a 3-year period.     

马铃薯甲虫防治技术及其抗药性研究进展

马铃薯甲虫Leptinotarsa decemlineata(Say)是世界上重要的毁灭性检疫害虫。国内外针对马铃薯甲虫的防治技术包括农业及物理防治(与非寄主作物合理倒茬轮作,诱集捕杀等)、生物防治(利用微生物农药和植物活性提取物防治,引进天敌控制)以及化学防治(使用有机磷、氨基甲酸酯、拟除虫菊酯类及其他新型杀虫剂防治)等。马铃薯甲虫对杀虫剂的抗性主要与体内代谢酶系、尤其是多功能氧化酶系活性升高有关;抗性遗传方式多为常染色体控制的不完全隐性遗传。抗性检测技术包括传统生物测定法和基因检测法,后者主要包括固相微型测序、单链构象多态性、双向等位特异PCR扩增等,这些新技术在抗药性监测中将发挥越来越重要的作用。