棉蚜对新烟碱类杀虫剂的抗性现状及其治理策略

棉蚜Aphis gossypii Glover是棉花生产中最严重的害虫之一。长期以来防治棉蚜主要依赖于化学杀虫剂,其中新烟碱类杀虫剂扮演着十分重要的角色,但由于其长期、大量的使用,棉蚜已对该类杀虫剂产生了较高水平的抗性,严重影响了对棉蚜的防治效果。抗性机制研究表明,棉蚜对新烟碱类杀虫剂产生抗性的机制主要涉及解毒代谢能力增强和靶标敏感性下降。细胞色素P450、羧酸酯酶、谷胱甘肽S-转移酶、UDP-葡糖基转移酶等解毒酶基因过量表达介导的解毒代谢增强和烟碱型乙酰胆碱受体β1亚基突变引起的靶标敏感性下降是棉蚜对新烟碱类杀虫剂产生抗性的关键。针对我国棉蚜对新烟碱类杀虫剂抗性问题突出的现状,为更好地利用该类药剂防治棉蚜,亟需根据棉蚜抗性机制制定合理的抗性治理策略。本文将从棉蚜对新烟碱类杀虫剂的抗性现状、抗性机制以及抗性治理策略等方面进行综述,以期为抗性棉蚜的科学治理提供参考。     

新烟碱类杀虫剂抗药性研究进展

新烟碱类杀虫剂是一类新开发的杀虫剂。研究表明，害虫野外种群对其敏感性差弄较大，现已有多种害虫对吡虫啉和啶虫脒产生了抗性。初步研究显示，马铃薯叶甲对吡虫啉抗性以不完全隐性的常染色体遗传；抗性似不稳定，交互抗性谱随虫种而变化，抗性形成可能与多功能氧化酶和酯酶有关。合理轮用和高剂量杀死策略是治理其抗性的有效措施。     

氟吡呋喃酮及其类似物研究进展

氟吡呋喃酮 (flupyradifurone) 是拜耳公司开发的新型丁烯内酯类杀虫剂,对刺吸式口器害虫具有优异的杀虫活性,与现有商品化新烟碱类杀虫剂相比,其作用机制独特,对蜜蜂低毒,自2014年上市以来就成为了农药学研究领域的热点。本文从氟吡呋喃酮的创制过程、生物活性及抗性、作用机制、代谢残留、对蜜蜂等非靶标生物的影响以及结构修饰等方面对该产品进行了综述。     

新烟碱类杀虫剂选择作用的分子机理

新烟碱类是一类重要的新颖杀虫剂,其发现是近20年来杀虫剂研究的一个里程碑。烟碱类和新烟碱类杀虫剂虽然都是作为后突触烟碱乙酰胆碱受体(nAChRs)的激动剂作用于昆虫的神经系统,但由于作用方式不同,新烟碱类杀虫剂对昆虫表现出选择性毒性。根据烟碱类和新烟碱类杀虫剂结构与活性的关系、分子特性以及它们与nAChR的结合部位和亚部位的选择性阐释了新烟碱类杀虫剂选择作用的分子机理。     

联苯八元氧桥环新烟碱增效剂的设计、合成及其增效活性

新烟碱杀虫剂作为一类重要的杀虫剂广泛应用于刺吸式口器害虫的防治。随着应用范围的扩大和应用时间的延长，新烟碱杀虫剂的抗性水平逐渐增加，其药效减弱。本文在前期研究的基础上,开发了一类联苯八元氧桥环新烟碱类似物，以苜蓿蚜Aphis Craccivora为测试靶标测试了目标化合物与新烟碱杀虫剂代表化合物吡虫啉联用时的增效作用，测试结果表明，目标化合物对吡虫啉有一定的增效作用。其中化合物D3在1 mg/L的联用浓度下对吡虫啉的增效倍数可达4.04倍，显著增加了吡虫啉对苜蓿蚜的杀虫活性，对解决传统新烟碱杀虫剂面临的抗性问题具有重要意义。     

害虫对Bt杀虫蛋白抗性相关受体蛋白互作网络分析

为对Bt杀虫蛋白与化学杀虫剂的协同使用提供理论指导，通过蛋白互作分析方法，以黑腹果蝇Drosophila melanogaster为模型，对化学杀虫剂与Bt杀虫剂作用受体以及抗性相关蛋白的互作网络进行研究。结果表明，Bt杀虫蛋白的27个受体在黑腹果蝇中共存在50个互作蛋白，其中有39个蛋白只与Bt杀虫蛋白抗性相关，11个蛋白还与化学杀虫剂抗性相关，这2类杀虫剂抗性互作网络交集较小，并且重叠蛋白的变异引起交互抗性的概率不大。表明Bt杀虫蛋白与化学杀虫剂产生交互抗性的概率较小，可以将Bt杀虫剂与化学杀虫剂协同使用，提高害虫防治效果，并有效克服或延缓害虫抗性产生。     

昆虫对双酰胺类杀虫剂抗性机制研究进展

双酰胺类杀虫剂是以昆虫鱼尼丁受体为作用靶标的新型杀虫剂,由于其作用机制独特,对多种鳞翅目害虫具有良好的防治效果而得到广泛应用。但已经有多种害虫的田间种群对该类药剂产生了抗性,甚至导致田间防治失败。本文在综述昆虫对双酰胺类杀虫剂抗性现状的基础上,重点总结了抗性机制方面的最新研究进展,并对今后的研究方向进行了展望,以期为进一步深入研究双酰胺类杀虫剂的抗性机制提供借鉴。     

江西奉新县试验金世纪防治蔬菜蚜虫效果优异

金世纪 (通用名称 3%啶虫脒 EC)是江苏克胜集团于 2000年成功开发的高效、低毒、低残留新型烟碱类杀虫剂.金世纪的杀虫机理与传统的杀虫剂有所不同.金世纪主要作用于昆虫神经接合部后膜,通过与乙酰胆碱受体结合,使昆虫异常兴奋,全身痉挛、麻痹而死;而拟除虫菊酯类作用于昆虫神经轴突;有机磷、氨基甲酸酯类则是抑制乙酰胆碱酯酶.金世纪不仅内吸性强、杀虫谱广、活性高,而且作用速度快、持效期长,而且对拟除虫菊酯类、有机磷类、氨基甲酸酯类产生抗性的害虫亦有效.     

二化螟对双酰胺类杀虫剂抗性的分子机制研究进展

新型双酰胺类杀虫剂已广泛用于保障水稻生产,而二化螟作为危害水稻生产的钻蛀性害虫,已经对该类杀虫剂产生了抗性,明确该类杀虫剂抗性分子机制,可为二化螟抗性快速检测和绿色防控提供技术支撑。本文在总结二化螟对双酰胺类杀虫剂抗性现状的基础上,重点综述了近年来有关其抗性分子机制研究的进展,主要包括解毒酶和转运蛋白基因过表达介导的代谢抗性,以及鱼尼丁受体基因突变介导的靶标抗性;指出了该研究领域在抗性分子检测、抗性新基因鉴定、抗性基因调控网络和多重抗性机制等方面存在的问题,并展望了其发展方向,认为：利用高通量测序技术检测害虫种群抗药性;利用多组学技术鉴定新抗性基因及调控网络,以探明多重抗性机制;将反向遗传学工具放射性配基结合及电生理技术深入验证抗性基因功能;需开发靶向抗性基因的dsRNA转基因作物、纳米农药及选择性新型化学杀虫剂,以达到杀虫剂减施增效的目的。     

N'-硝基缩氨基胍类化合物的合成及其杀虫活性

为寻找新的杀虫先导化合物,采用活性亚结构拼接法,将新烟碱类和缩氨脲类杀虫剂的活性结构单元组建到同一分子中,设计合成了25个N'-硝基缩氨基胍类目标化合物,其中22个为新化合物,其结构经核磁共振氢谱和元素分析确证。初步杀虫活性测定结果表明,在500 μg/mL剂量下,所有目标化合物对烟粉虱Bemisia tabaci(Gennadius)均具有一定的杀虫活性,其中化合物 3e和3i 的致死率达80%以上,但对粘虫Mythimna separata(Walker)则基本无活性。     

Effects of mutations in Drosophila nicotinic acetylcholine receptor subunits on sensitivity to insecticides targeting nicotinic acetylcholine receptors

Several strains of Drosophila melanogaster possess mutant alleles in nicotinic acetylcholine receptor (nAChR) subunits, Dα1 and Dβ2 that confer resistance to neonicotinoids such as imidacloprid and nitenpyram, and Dα6, that confers resistance to spinosyns. These mutant strains were bioassayed with a selected set of nAChR active insecticides including neonicotinoids, spinosad, and sulfoxaflor, a new sulfoximine insecticide. All of the neonicotinoids examined, except dinotefuran showed reduced insecticidal efficacy on larvae of the Dα1 mutant, suggesting that this subunit may be important in the action of these insecticides. All of the neonicotinoids, including dinotefuran, showed reduced insecticidal efficacy on larvae possessing the Dβ2 mutation. A similar pattern of broad neonicotinoid resistance to that of Dβ2 alone was also observed for larvae with both the mutations (Dα1 + Dβ2). The Dβ2 mutation exhibited a lower level of cross-resistance to sulfoxaflor (<3-fold) than to any of the neonicotinoids (>13-fold). In contrast, there was no cross-resistance for any of the neonicotinoids or sulfoxaflor in adult flies with the Dα6 mutation, which confers high levels of resistance to spinosad. Thus in the D. melanogaster strains studied, target site resistance observed for the neonicotinoids and the spinosyns does not translate directly to resistance towards sulfoxaflor.     

Toxicology of insecticides to mammals

Many insecticides target structures or functions in non-target species, including mammals. This is particularly true of those that target the insect nervous system, such as the organochlorines, anticholinesterases and GABA antagonists. Another group of insecticides target structures or functions not present in mammals, and this group of insecticides has considerable target species specificity, but there are often potential targets in mammals. Octopamine is closely related to adrenaline and amitraz (an octopamine receptor agonist) and acts in mammals at α2-adrenergic receptors. Although there are potential targets in mammals for juvenile hormone mimics and ecdysone receptor agonists, there is no evidence that the mammalian toxicity of either group is related to their insecticidal activity. Nor do chitin synthesis inhibitors have high mammalian toxicity. Copyright © 2012 Society of Chemical Industry     

新烟碱类杀虫剂吡虫啉和噻虫嗪的代谢研究进展

对新烟碱类杀虫剂吡虫啉和噻虫嗪的化学结构特点及代谢研究进展进行了综述,重点对其在哺乳动物、植物和昆虫体内的代谢途径及相关的生物代谢酶进行了阐述。吡虫啉和噻虫嗪在环境中可被动物、植物、微生物及昆虫所代谢,与其生物代谢相关的酶主要是微粒体细胞色素P450同工酶和醛氧化酶,其中,P450同工酶可催化吡虫啉和噻虫嗪发生羟基化、去饱和、脱烷基、硝基还原等代谢反应,而醛氧化酶主要催化其硝基部分的还原。吡虫啉和噻虫嗪经过代谢后其生物活性通常有所降低,但也有部分代谢产物的活性反而升高,增加了其对昆虫的毒性以及对非靶标生物的风险。明确吡虫啉和噻虫嗪的代谢途径、代谢产物及其生物活性,对于了解新烟碱类杀虫剂的代谢机理,以及安全有效地使用该类杀虫剂具有重要意义。     

Thiamethoxam acts as a target‐site synergist of spinosad in resistant strains of Frankliniella occidentalis

BACKGROUND: Previous studies have suggested that the resistance mechanism towards spinosad in Frankliniella occidentalis (Pergande) is an altered target site. Like the neonicotinoids, the spinosyns act on nicotinic acetylcholine receptors (nAChRs) in insects, but at a distinct site. The changes in nAChRs related to spinosad resistance in thrips might involve interaction with neonicotinoids. In this study, the efficacy of spinosad and neonicotinoids, alone and in combination, was evaluated in susceptible and spinosad‐resistant thrips strains. RESULTS: The neonicotinoids tested were imidacloprid, thiacloprid, acetamiprid, thiamethoxam and clothianidin. No cross‐resistance was shown between spinosad and any of the neonicotinoids. However, an increased toxicity was observed when a mixture of spinosad with thiamethoxam or clothianidin was tested. No synergism was found in the susceptible strains. The more spinosad‐resistant the thrips strain, the stronger was the synergism. CONCLUSION: Data suggest that spinosad and thiamethoxam may interact at the nAChRs in spinosad‐resistant thrips, facilitating enhanced insecticidal action. Copyright © 2012 Society of Chemical Industry     

Applied aspects of neonicotinoid uses in crop protection

Neonicotinoid insecticides comprise seven commercially marketed active ingredients: imidacloprid, acetamiprid, nitenpyram, thiamethoxam, thiacloprid, clothianidin and dinotefuran. The technical profiles and main differences between neonicotinoid insecticides, including their spectrum of efficacy, are described: use for vector control, systemic properties and versatile application forms, especially seed treatment. New formulations have been developed to optimize the bioavailability of neonicotinoids through improved rain fastness, better retention and spreading of the spray deposit on the leaf surface, combined with higher leaf penetration. Combined formulations with pyrethroids and other insecticides are also being developed with the aim of broadening the insecticidal spectrum of neonicotinoids and to replace WHO Class I products from older chemical classes. These innovative developments for life-cycle management, jointly with the introduction of generic products, will, within the next few years, turn neonicotinoids into the most important chemical class in crop protection.     

双酰胺类农药生物活性、生态毒性及残留行为研究进展

双酰胺类农药是继新烟碱类农药之后备受关注的一类杀虫剂，作用靶标为鱼尼丁受体和γ-氨基丁酸受体，对鳞翅目害虫的防治效果优异。随着双酰胺类农药的广泛应用，其对非靶标生物和水生生态环境产生了潜在威胁，且靶标害虫的抗药性问题也日益凸显。本文综合国内外研究进展，从生物活性、生态毒性、分析方法、环境行为和风险评估5个方面对双酰胺类农药的研究进行了综述，对后续研究方向进行了展望，可为该类农药的精准应用、风险规避和有效管理提供科学参考。     

Neonicotinoids-from zero to hero in insecticide chemistry

In recent years, neonicotinoids have been the fastest-growing class of insecticides in modern crop protection, with widespread use against a broad spectrum of sucking and certain chewing pests. As potent agonists, they act selectively on insect nicotinic acetylcholine receptors, their molecular target site. The discovery of neonicotinoids can be considered as a milestone in insecticide research and facilitates greatly the understanding of the functional properties of insect nicotinic acetylcholine receptors. Because of the relatively low risk for non-target organisms and environment, the high target specificity of neonicotinoid insecticides and their versatility in application methods, this important class has to be maintained globally for integrated pest management strategies and insect resistance management programmes. This review comprehensively describes particularly the origin, structure and bonding as well as associated properties of neonicotinoid insecticides.     

Application of computational methods in the analysis of pesticide target-site and resistance mechanisms

Meta-diamide insecticides including broflanilide have a high insecticidal activity by acting on RDL GABA receptors. Both membrane potential assays and docking studies suggest that the target site of meta-diamides is different from that of conventional noncompetitive inhibitors, such as fipronil. In fact, meta-diamides are effective against cyclodiene- and fipronil-resistant pests that carry target-site mutations. Dinotefuran uniquely possesses a tetrahydrofuran ring, whereas other neonicotinoids possess aromatic rings. Moreover, dinotefuran has been reported to be effective against imidacloprid-resistant strains. A docking study predicted the weak binding of dinotefuran to cytochrome P450s which are associated with imidacloprid resistance. Metabolic assays revealed that dinotefuran was not metabolized by these cytochrome P450s. These findings suggest that the lack of metabolic activity of P450s against dinotefuran causes a low level of cross-resistance.     

Chemical structure and physical properties of candidate insecticides in relation to residual toxicity to adult mosquitos

Data are presented on changes in physical properties and insecticidal activity resulting from modifications in chemical structure in two groups of compounds. The first group consists of propoxur and three closely related N-methylcarbamates and the corresponding N-acetyl compounds The parent compounds are all highly toxic to adult mosquitos by topical application in solution and deposits from water-dispersible powder formulations on plywood and plaster of Paris panels have long residual activity. N-acetylation is not accompanied by excessive loss of toxicity to mosquitos, but increases volatility to the extent that none of the four N-acetyl derivatives can be considered as potential residual insecticides. The second group consists of tetrachlorvinphos and related vinyl phosphates and vinyl phosphorothionates which show a wide range of toxicity both to adult mosquitos and to mammals.