Resistance development,cross-resistance,and fitness costs associated with Aphis gossypii resistance towards sulfoxaflor and acetamiprid in different geographical regions

Aphis gossypii has become increasingly difficult to manage due to its strong insecticide resistance.In the laboratory,we established sulfoxaflor-resistant and acetamiprid-resistant strains in two A.gossypii populations with different basal insecticide resistance levels,and evaluated the effects of basal insecticide resistance on the resistance development and cross-resistance,as well as differences in fitness.Under the same selection pressure,Yarkant A.gossypii(with low basal insecticide resistance)evolved resistance to sulfoxaflor and acetamiprid more quickly than Jinghe A.gossypii(with high basal insecticide resistance),and the evolution of A.gossypii resistance to sulfoxaflor developed faster than acetamiprid in both Yarkant and Jinghe,Xingjiang,China.The sulfoxaflor-resistant strains selected from Yarkant and Jinghe developed significant cross-resistance to acetamiprid,imidacloprid,thiamethoxam and pymetrozine;while the acetamiprid-resistant strains developed significant cross-resistance to sulfoxaflor,imidacloprid,thiamethoxam,pymetrozine,and chlorpyrifos.The relative fitness of A.gossypii decreased as the resistance to sulfoxaflor and acetamiprid developed.The relative fitness levels of the sulfoxaflor-resistant strains(Yarkant-SulR and Jinghe-SulR)were lower than those of the acetamipridresistant strains(Yarkant-AceR and Jinghe-AceR).In addition,the relative fitness levels of sulfoxaflor-and acetamiprid-resistant strains were lower in Jinghe than in Yarkant.In summary,basal insecticide resistance of A.gossypii and insecticide type affected the evolution of resistance to insecticides in A.gossypii,as well as cross-resistance to other insecticides.The sulfoxaflor-and acetamiprid-resistant A.gossypii strains had obvious fitness costs.The results of this work will contribute to the insecticide resistance management and integrated management of A.gossypii.

棉蚜Aphis gossypii Glover在不同寄主上的体色分化研究

对不同寄主上不同时期棉蚜的体色分化进行比较研究 结果表明 ,棉蚜自然种群由黄色型和绿色型 2种个体组成 .在木槿、石榴和花椒 3种越冬寄主上 ,早春以绿色型个体为主 ,春末夏初黄色型个体逐渐占优势 ,夏末秋初又以绿色型个体为主 ;在夏季寄主棉花上 ,黄色型个体一直占优势 ,其中 5～ 6月份棉花苗期可见到部分绿色型个体 ,所占比例与越冬寄主上棉蚜迁出时所占的比例基本接近 .在室内不同温度条件下连续饲养不同体色棉蚜的试验结果表明 ,绿色型棉蚜可分化出绿色型和黄色型 2种后代 ,后代的体色变化与温度密切相关 ,在温度较高时黄色型后代占优势 ,在温度较低时绿色型后代占优势 ,而且黄色型后代随温度的降低也会产生出绿色型后代 .系统饲养黄色干母的后代还发现 ,不论饲养温度如何变化 ,其后代均为黄色型 ,表明自然界有

山东省主要菜区瓜(棉)蚜(Aphis gossypii Glover)抗药性及机理研究

利用毛细管点滴法测定了山东省 4个主要菜区瓜 (棉 )蚜 (Ap his gossypiiGlover)对氰戊菊酯、吡虫啉、氧乐果和灭多威的抗性。结果表明 ,聊城种群对氰戊菊酯的抗性高达 12 1710 .1倍 ,对吡虫啉、氧乐果和灭多威也分别产生了 9.6、2 9.4及 7.9倍的抗性 ;寿光种群对氰戊菊酯的抗性也高达 2 74 59.3倍 ,对吡虫啉、氧乐果和灭多威的抗性分别为 4 .1、18.1及 2 .9倍 ;苍山、泰安两种群对 4种药剂的抗性亦有不同程度的提高。离体酶活性和增效剂测定结果表明 ,聊城种群的抗药性与多功能氧化酶、羧酸酯酶、谷胱甘肽转移酶和乙酰胆碱酯酶活力提高均有关系。

Cloning and Sequencing of Two Acetylcholinesterase cDNA Fragments from Cotton Aphid,Aphis gossypii Glover

Two acetylcholinesterase (AChE) genes cDNA fragments,Ag.acel and Ag.ace2,have been cloned from cotton aphid,Aphis gossypii Glover using degenerate primers with RT-PCR technique.Ag.acel gene cDNA fragment is of 282?bp encoding 94 amino acids,and Ag.ace2 gene cDNA fragment is of 264?bp encoding 88 amino acids.Both two putative AChE genes cDNA fragments share numerous similarities with those cloned from other insects.This is the first report of two AChE cDNA fragment sequences in the insect species,which provided the direct evidence of multiple AChE existence in insects.

A sublethal concentration of afidopyropen suppresses the population growth of the cotton aphid, Aphis gossypii Glover(Hemiptera: Aphididae)

The cotton aphid,Aphis gossypii Glover(Hemiptera:Aphididae),is an important insect pest of cotton crops worldwide.The objectives of this study were to determine the acute toxicity of afidopyropen and whether there are any effects of sublethal concentrations of afidopyropen on the biological characteristics of A.gossypii.The results showed that afidopyropen possesses high acute toxicity to adult A.gossypii with a 72 h LC_(50) value of 1.062 mg L^(–1).A sublethal concentration(LC_(10))of afidopyropen significantly decreased adult longevity,fecundity and oviposition days of female adults in both F0 and F1 generations.The total pre-adult survival of F_(1) progeny was also significantly reduced by 30%at the LC_(10) of afidopyropen.In addition,the nymph developmental time,pre-adult period,adult pre-reproductive period(APRP),and total pre-reproductive period(TPRP)of the F1 progeny were significantly prolonged compared with the control.Several population parameters,including the net reproductive rate(R_(0)),intrinsic rate of increase(r)and finite rate of increase(λ)of F_(1) progeny were significantly decreased by a sublethal afidopyropen concentration exposure.These results indicated that sublethal concentration of afidopyropen can significantly suppress A.gossypii population growth.It would be useful for assessing the overall effects of afidopyropen on A.gossypii.

棉蚜Aphis gossypii Glover在棉花不同品种上的生长繁育和排蜜的研究

在室內饲养不同品种棉苗上的棉蚜,其生长、敏育和排蜜情况有显著差异。我们对新疆主栽的6个棉花品种上棉蚜的平均相对生长量、个体生殖力、种群数量增殖率和棉蚜排泄的蜜滴直径、蜜滴重量、棉蚜排蜜频率等进行了研究,并对棉花品种的內部含糖量进行了测定。在供试的棉花品种中,“军棉一号”和“大铃棉”叶片內部含糖量高,其相应地棉蚜生长发育快,排蜜量也多;长绒棉“新海三号”和“新海七号”次之;而“新陆早一号”和“新陆中一号”上的棉蚜相对生长发育慢,排蜜量也少。

棉蚜(Aphis gossypii)种群寄主分化和季节分化的微卫星引物PCR研究

通过对棉蚜群体进行室外观察、室内培养和分子遗传标记的 DNA多态性分析 (用 3个微卫星序列为引物进行PCR)等研究 ,结果表明 :1 .冬寄主 (木槿、石榴和花椒 )上棉蚜种群分化较小 (种群相似性指数在 0 .833～ 0 .91 7之间 ) ,而冬寄主种群和夏寄主 (棉花和南瓜 )种群之间有较大的分化 (种群相似性指数在 0 .589～ 0 .756之间 )。2 .棉蚜自然种群是由体色不变的生物型 (干母为黄色 ,其后代始终为黄色 )和体色可变型生物型 (干母为绿色 ,其后代有绿色和黄色两种体色 )组成的混合种群。3.黄色小型蚜 (伏蚜 )来源于混合类群 ,但主要来自绿色干母多代选择分化的黄色后代 。

Effect of Transgenic Bt plus CpTI Cotton on Carboxylesterase and Acetylcholinesterase of Cotton Aphid Aphis gossypii

[Objective] The research aimed to assess the effect of transgenic Bt plus CpTI cotton variety SGK321 on carboxylesterase and acetylcholinesterase of cotton aphid Aphis gossypii and provide theoretical basis for studying the biosafety of transgenic cotton.[Method] Cotton aphids were fed with SGK321 and Shiyuan321（normal parental varieties） for over 40 generations.Enzyme activities were compared between cotton aphids feeding on SGK321 for 1,2,3,41,42 and 43 generations with those on Shiyuan321.[Result] The carboxylesterase activity of cotton aphids feeding on SGK321 for 1 generation was significantly higher than those feeding on Shiyuan321.Acetylcholinesterase activity of cotton aphids feeding on SGK321 for 1,2 and 3 generations were significantly higher than those feeding on Shiyuan321 in the same generation.But there was no significant difference of enzyme activity between cotton aphids feeding on SGK321 for a long term and those feeding on parental cotton.[Conclusion] The cotton aphid that feeding on transgenic Bt plus CpTI cotton SGK321 for a long time has adaptivity to SGK321 by regulating the detoxifying enzyme.

七星瓢虫(Coccinella septempunctata)捕食棉蚜(Aphis gossypii)的功能反应:实验与模拟(英文)

室内研究了５个温度条件（１５、２０、２５、３０和３５±０．５℃）下，七星瓢虫（Ｃｏｃｉｎｅｌａｓｅｐｔｅｍｐｕｎｃｔａｔａ）５个捕食虫态对棉蚜（Ａｐｈｉｓｇｏｓｙｐｉ）３个体积组的功能反应。测试温度范围内，瞬时攻击率（ｓｅａｒｃｈｒａｔｅ）和处置时间（ｈａｎ－ｄｌｉｎｇｔｉｍｅ）随捕食者龄期的增长而增加；每一捕食者虫态内，搜索率随猎物体积的增加而上升，而处置率则下降；搜索率随温度增加直线上升，而处置率则呈曲线上升。田间罩笼内研究了５个捕食者虫态对棉蚜混合种群的捕食功能，其捕食率远远低于室内实验。应用复合捕食方程并结合叶面积的影响对七星瓢虫捕食棉蚜的功能进行了模拟研究，且模拟值与观察值吻合程度较好。本研究表明，虽然七星瓢虫—棉蚜系统比较复杂，可以应用本研究探讨的方法建立模拟模型，以准确预测田间棉蚜的种群动态。

The influence of Tetranychus cinnabarinus-induced plant defense responses on Aphis gossypii development

Carmine spider mites （Tetranychus cinnabarinus） and cotton aphids （Aphis gossypii） are both serious pests of cotton, and cause reductions in yields of this key agricultural crop. In order to gain insights into how plant defense responses induced by one herbivore species affect the behavior and performance of another, we examined how infestation with T. cinnabarinus influences the development of A. gossypfi using cotton as a model. In this study, we measured the activities of several important biochemical markers and secondary metabolites in the leaves of cotton seedlings responding to infestation by T. cinnabarinus. Furthermore, the influences of T. cinnabarinus infestation on the development ofA. gossypfi in cotton were also examined. Our data showed that the activities of several key defense enzymes, including phenylalanine ammonia-lyase （PAL）, peroxidase （POD）, lipoxygenase （LOX）, and polyphenol oxidase （PPO）, were substantially increased in cotton seedlings responding to spider mite infestation. Further, the contents of gossypol and condensed tannins, key defensive compounds, were significantly enhanced in leaves of cotton seedlings following T. cinnabarinus infestation. Moreover, the T. cinnabarinus-induced production of defense enzymes and secondary metabolites was correlated with infestation density. The developmental periods of A. gossypii on cotton seedling leaves infested with T. cinnabarinus at densities of 10 and 15 individuals cm-2 were 1.16 and 1.18 times that of control, respectively. Meanwhile, the mean relative growth rates of A. gossypfi on cotton leaves infested with T. cinnabarinus at densities of 8, 10 and 15 individuals cm-2 were significantly reduced. Therefore, these data suggested that the developmental periods of A. gossypfi were significantly lengthened and the mean relative growth rates were markedly reduced when cotton aphids were reared on plants infested with high densities of spider mites. This research sheds light on the role that inducible defense responses played in plant-mediated interspecific interactions between T. cinnabarinus and A. gossypfi.

The damage risk evaluation of Aphis gossypii on wheat by host shift and fitness comparison in wheat and cotton

Aphids are considered as one of the key pests for wheat production worldwide. Major aphid species that infest wheat in China include Sitobion avenae, Rhopalosiphum padi, Schizaphis graminum and Metopolophium dirhodum. However, during our wheat field survey in Wenshang County of Shangdong＇Province, China, we observed that Aphis gossypii can feed on wheat. The damage risk of A. gossypii on wheat was assessed using host shift method. A population of A. gossypii collected from a wheat field in 2015 and another population reared on cotton under laboratory conditions for a decade without exposure to insecticides were used in the study. The results of host shift demonstrated that the A. gossypfi colony from wheat has not yet developed wheat specialization. Moreover, the assessment of A. gossypii fitness on wheat and cotton showed that fecundity and net reproductive rate of A. gossypii population fed on wheat was significantly higher comparing to the population fed on cotton, whether the initial host of A. gossypii population was wheat or cotton. This study raises a warning that the cotton aphid has potential to establish well on wheat and it may cause significant effects under specific circumstances. Therefore, future studies are required to evaluate the effects of A. gossypfi on wheat production.

Comparative transcriptional analysis and identification of hub genes associated with wing differentiation of male in Aphis gossypii

Background:Aphis gossypii Glover(Hemiptera:Aphididae),a worldwide polyphagous phloem-feeding agricultural pest,has three wing morphs(winged parthenogenetic female,gynopara,and male)in the life cycle.The exclusive males could fly from summer hosts to winter hosts,which are essential for gene exchanges of cotton aphid populations from different hosts or regions.However,the molecular mechanism of wing differentiation of male in A.gossypii remains unclear.Results:Morphological observation of male A.gossypii showed that there is no distinct difference in the external morphologies of the 1st and 2nd instar nymphs.The obvious differentiation of wing buds started in the 3rd instar nymph and was visible via naked eyes in the 4th instar nymphal stage,then adult male emerged with full wings.According to morphological dynamic changes,the development of wings in males were divided into four stages:preliminary stage(the 1st instar to 2nd instar),prophase(the 3rd instar),metaphase(the 4th instar),anaphase(the 5th instar).Results of feeding behavior monitoring via EPG(electrical penetration graph)technology indicated that although the male cotton aphids had strong desire to feed(longer duration of C 55.24%,F 5.05%and Pd waves 2.56%),its feeding efficiency to summer host cotton was low(shorter E13.56%and E2 waves 2.63%).Dynamic transcriptome analysis of male aphid at 5 different developmental periods showed that in the 3rd instar nymph,the number of up-regulated DEGs was significant increased,and time-course gene transcriptional pattern analyses results also showed that numerous genes categorized in clusters 3,5,and 8 had the highest expressed levels,which were consistent with morphological changes of wing buds.These results indicate that the 3rd instar nymph is the critical stage of wing bud differentiation in males.Furthermore,through pathway enrichment analysis of DEGs and WGCNA,it revealed that the neuroactive ligand-receptor interaction,Ras signaling pathway,dopaminergic synapse,circadian entrainment and the corresponding hub genes of PLK1,BUB1,SMC2,TUBG,ASPM,the kinesin family members(KIF23,KIF20,KIF18-19)and the novel subfamily of serine/threonine(Aurora kinase A and Aurora kinase B)probably played an important role in the critical stage of wing bud differentiation.Conclusion:This study explored morphological changes and genes transcriptional dynamics males in cotton aphid,revealed the phenomenon of low feeding efficiency of winged males on summer host cotton,and identified key signaling pathways and potential hub genes potentially involved in wing bud differentiation of male in A.gossypii.

Biochemical Characterization of Detoxifying Enzymes in Dimethoate-Resistant Strains of Melon Aphid, Aphis gossypii(Hemiptera: Aphididae)

The melon aphid, Aphis gossypii Glover (Hemiptera: Aphididae), is a highly polyphagous sap sucking pest on wide varieties of crops including cotton and vegetables. It is a notorious vector of many plant viruses that are persistently and non-persistently transmitted. In nature, aphids are regulated by their natural enemies. However, chemical control remains a major management tool even though resistance to insecticides has been documented worldwide. A better understanding of mechanisms by which insecticide resistance occurs and its early detection is desirable to develop effective management strategies. The present investigation was conducted to study the development of resistance to an organophosphate (OP) compound-dimethoate, identify biochemical mechanism(s) involved in resistance and study cross-resistance to imidacloprid in laboratory selected A. gossypii strains in comparison to susceptible strains. Bioassay studies revealed that the LC50 values increased dramatically with dimethoate selection in resistant strains and the resistance ratio (RR) was 270-, 243- and 210-fold greater than that of the susceptible strains by 30th generation. Further, biochemical assays revealed enhanced activities of carboxylesterases (CarE), glutathione S-transferases (GSTs) and cytochrome P450-mediated p-Nitroanisole O-demethylase (PNOD) in resistant strains supporting their role in dimethoate detoxification. This study thus revealed that enhanced activity of detoxifying enzymes viz., CarE, GSTs and PNODs is one of the mechanisms underlying dimethoate resistance in A. gossypii collected from South India. Interestingly, the possibility of negatively correlated cross-resistance to imidacloprid was identified in three OP- resistant strains exhibiting 2.97-, 2.56- and 3.76-fold sensitivity to imidacloprid (a novel neonicotinoid). This indicated that the latter was less affected by the resistance mechanism(s) present.

Biochemical Characterization of Detoxifying Enzymes in Dimethoate-Resistant Strains of Melon Aphid, <i>Aphis gossypii</i>(Hemiptera: Aphididae)

The melon aphid, Aphis gossypii Glover (Hemiptera: Aphididae), is a highly polyphagous sap sucking pest on wide varieties of crops including cotton and vegetables. It is a notorious vector of many plant viruses that are persistently and non-persistently transmitted. In nature, aphids are regulated by their natural enemies. However, chemical control remains a major management tool even though resistance to insecticides has been documented worldwide. A better understanding of mechanisms by which insecticide resistance occurs and its early detection is desirable to develop effective management strategies. The present investigation was conducted to study the development of resistance to an organophosphate (OP) compound-dimethoate, identify biochemical mechanism(s) involved in resistance and study cross-resistance to imidacloprid in laboratory selected A. gossypii strains in comparison to susceptible strains. Bioassay studies revealed that the LC50 values increased dramatically with dimethoate selection in resistant strains and the resistance ratio (RR) was 270-, 243- and 210-fold greater than that of the susceptible strains by 30th generation. Further, biochemical assays revealed enhanced activities of carboxylesterases (CarE), glutathione S-transferases (GSTs) and cytochrome P450-mediated p-Nitroanisole O-demethylase (PNOD) in resistant strains supporting their role in dimethoate detoxification. This study thus revealed that enhanced activity of detoxifying enzymes viz., CarE, GSTs and PNODs is one of the mechanisms underlying dimethoate resistance in A. gossypii collected from South India. Interestingly, the possibility of negatively correlated cross-resistance to imidacloprid was identified in three OP- resistant strains exhibiting 2.97-, 2.56- and 3.76-fold sensitivity to imidacloprid (a novel neonicotinoid). This indicated that the latter was less affected by the resistance mechanism(s) present.

不同虫龄异色瓢虫对棉蚜的潜在控制能力评价

为明确天敌昆虫对黄瓜害虫的自然控制作用,以优势天敌昆虫异色瓢虫为对象,黄瓜棉蚜为猎物,采用HollingⅡ功能反应数学模型、寻找效应模型和HasselⅡ数学模型,研究不同虫龄异色瓢虫对黄瓜棉蚜的捕食功能反应。结果表明,在试验范围内,不同虫龄异色瓢虫对棉蚜的捕食量与棉蚜密度正相关,捕食功能曲线符合HollingⅡ模型,1~4龄异色瓢虫对棉蚜的最大日捕食量分别为31.25、66.225、192.308和370.370头,成虫最大日捕食量为124.20头;4龄幼虫对棉蚜的控制能力最强,a′/T_(h)值最高(372.119),其次为3龄幼虫、成虫、2龄幼虫,1龄幼虫对棉蚜的控制能力相对最弱,a′/T_(h)值最低(27.366)。不同龄期异色瓢虫的寻找效应与棉蚜密度均呈负相关,且在相同猎物密度下,4龄异色瓢虫对棉蚜的寻找效应相对最高。异色瓢虫成虫的捕食作用存在较强的种内干扰反应,拟合模型为E=0.6625P^(-0.8307)。综上表明,不同虫龄异色瓢虫对棉蚜均具有不同程度的捕食能力,尤其高龄幼虫和成虫捕食作用较强。

吡虫啉和苦参碱及其复配对毛叶苕子蚜虫的毒力测定及田间防效

为防治绿肥作物毛叶苕子上蚜虫危害,筛选出对毛叶苕子蚜虫高效配方,选择作用机理不同的吡虫啉和苦参碱,开展了最佳配比筛选及田间防治效果评价。结果表明,吡虫啉和苦参碱4种混配组合(有效成分含量之比分别为1∶10、1∶20、1∶40和1∶80)对毛叶苕子上棉蚜的毒力均表现为增效作用,其中1∶20组合的共毒系数最高,为376.14。选择该配比进行的田间药效试验表明,该混剂组合在有效成分用量为5.94 g/hm^(2)时,药后3、7 d的防治效果均显著高于单剂,最高防效近80%,可作为今后混剂的开发或生产中防治毛叶苕子蚜虫的推荐药剂。

棉蚜对不同品种枸杞的适应性

为了明确棉蚜(Aphis gossypii Glover)对宁夏地区不同主栽枸杞品种的适应性,利用年龄-阶段两性生命表对棉蚜取食不同品种枸杞后生长发育及种群参数进行研究。结果表明,取食不同枸杞品种的棉蚜产蚜期、产蚜量和寿命存在显著差异。其中取食‘宁杞1号’的棉蚜产蚜期、总寿命、成虫寿命和产蚜量分别为8.61 d、15.22 d、9.58 d和11.78头,显著低于‘宁杞5号’(分别为9.71 d、16.14 d、10.78 d和15头)、‘宁杞7号’(分别为9.71 d、15.87 d、10.52 d和14.21头)和‘宁杞10号’(分别为11.08 d、17.80 d、12.24 d和17.40头)。取食不同枸杞品种的棉蚜净增殖率(R0)、总繁殖率(GRR)、内禀增长率(r)、平均世代周期(T)和周限增长率(λ)等参数存在显著差异。其中取食‘宁杞1号’棉蚜的R0、GRR、r和λ值(分别为7.07、14.13、0.21 d^(-1)和1.24 d^(-1))均显著低于‘宁杞5号’(分别为10.5、16.9、0.26 d^(-1)和1.29 d^(-1))、‘宁杞7号’(分别为11.37、18.47、0.27 d^(-1)和1.30 d^(-1))和‘宁杞10号’(分别为14.5、20.41、0.28 d^(-1)和1.32 d^(-1));取食‘宁杞1号’棉蚜的t值(9.17 d)显著低于‘宁杞10号’(9.5 d),高于‘宁杞7号’(9.01 d)。综上表明,棉蚜取食4个枸杞品种均能正常发育并完成整个世代,但在不同品种枸杞上的适应性不同,在‘宁杞10号’品种上的适应性最好,‘宁杞5号’和‘宁杞7号’次之,‘宁杞1号’的适应性最低。因此,可以考虑利用棉蚜适应性较低的品种作为宁夏地区主栽枸杞对棉蚜进行防控。

金龟子绿僵菌CQMa421对棉蚜、绿盲蝽的田间防效

棉花是我国重要的经济作物,虫害严重制约了棉花生产,造成棉农的经济损失。目前,化学杀虫剂仍是防治棉花虫害的主要手段,长期使用化学杀虫剂导致棉蚜Aphis gossypii、绿盲蝽Apolygus lucorum产生抗药性,降低防治效果。本研究使用80亿孢子/mL金龟子绿僵菌CQMa421可分散油悬浮剂防治棉蚜、绿盲蝽,室内生测结果表明,金龟子绿僵菌CQMa421能有效侵染棉蚜和绿盲蝽,随着浓度的升高,对棉蚜和绿盲蝽的毒力增强。田间试验结果表明,该药剂能有效控制棉花主要害虫棉蚜和绿盲蝽。采用1200 mL/hm 2用量,药后14 d对棉蚜的防效达94.42%;采用1350 mL/hm 2用量,药后14 d对绿盲蝽的防效分别达到87.25%(新疆),91.62%(湖北)。

助剂对植保无人机喷施雾滴沉积特性和棉蚜防效的影响

【目的】探明植保无人机喷施农药时添加助剂对雾滴沉积特性和棉蚜防治效果(防效)的影响。【方法】选用大疆T30植保无人机在棉花蕾期进行田间喷雾试验,比较添加6种助剂(牙克透、倍达通、植物三餐、农健飞、奇功和倍倍加)对39%螺虫·噻嗪酮悬浮剂的雾滴粒径、密度、覆盖率和沉积量及棉蚜防效的影响。【结果】与不添加助剂的对照相比,添加6种助剂均能提高棉花上部、中部和下部叶片上的雾滴密度、覆盖率和沉积量。添加倍倍加、倍达通处理的雾滴粒径、密度、覆盖率和沉积量均较大,棉株上部、中部和下部叶片上的雾滴密度、覆盖率和沉积量均显著高于对照处理。添加6种助剂的各处理在药后1 d、3 d、7 d和14 d对棉株上部、中部和下部棉蚜的防效均高于对照处理,其中,添加倍倍加处理的防效最好,倍达通处理次之。【结论】添加助剂倍倍加和倍达通可改善雾滴沉积特性,对棉蚜具有较好的防效,对39%螺虫·噻嗪酮悬浮剂防治棉蚜具有很好的增效作用。

13种植物甲醇提取物对瓜蚜生物活性的影响

【目的】为了明确植物提取物对瓜蚜(Aphis gossypii Glover)的生物活性,为植物源农药开发利用提供新途径。【方法】本研究采用喷雾法施药,测定13种植物甲醇提取物对瓜蚜的室内杀虫活性与趋避活性;将具有良好活性的黄连木(P.chinensis)和川牛膝(C.officinalis)植物提取物制备成乳油,通过田间试验测定制剂防效。【结果】在杀虫活性测定中,处理72 h后,黄连木甲醇提取物对瓜蚜的活性最高,校正死亡率达到了81.11%;在对瓜蚜趋避活性测定中,毛泡桐(P.tomentosa)甲醇提取物对瓜蚜24 h的驱避率达到75.14%,薄荷(M.pulegium)、糙苏(P.umbrosa)和川牛膝甲醇提取物对瓜蚜的趋避率均高于50%;在不同植物甲醇提取物混配活性测定试验中,黄连木甲醇提取物与川牛膝、糙苏、毛泡桐、短序荚蒾(Viburnum brevipes)甲醇提取物的混配效果优于其他组合;试验研制了20%黄连木和川牛膝甲醇提取物乳油,配方为黄连木甲醇提取物10%、川牛膝甲醇提取物10%、二甲基亚砜47%、农乳500#25%、NP-2乳化剂8%。田间试验方法测定20%黄连木川牛膝甲醇提取物乳油对瓜蚜的田间防效,以10%吡虫啉可湿性粉剂为阳性对照,试验结果表明20%黄连木川牛膝甲醇提取物制剂药后14 d防治效果达到了75.26%,与阳性对照无显著差异。【结论】黄连木、糙苏、毛泡桐和川牛膝的甲醇提取物对蚜虫具有一定的生物活性,值得进一步研究。