Impacts of Climate Change on the Occurrence Degree of Cotton Aphids in Huang-Huai-Hai and Yangtze River Basins

[Objective] The aim was to analyze the impacts of climate change （tem- perature and precipitation） on the occurrence degree of cotton aphids. [Method] Ec- onometric models were established to explore the impacts of climate change on the occurrence degree of cotton aphids based on the observation data from 50 counties in Huang-Huai-Hai and Yangtze River basins in 1991-2010, including variables on the occurrence degree of cotton aphids, temperature and precipitation, and other factors. [Result] There were significant differences in the effects of temperature and precipitation changes on the occurrence degrees of cotton aphid in different growth stages, and even in the same growth stage, the cotton aphids had different responses to the changes of temperature and precipitation in different re- gions. [Conclusion] It should give full consideration to the climatic conditions in dif- ferent periods of different regions, and it should adopt proper measures to control the cotton aphids on the basis of figuring out the occurrence rule of cotton aphid, so as to ensure cotton production.

Occurrence Rule and Forecast Method of Cotton Aphid in Poyang Lake Area in Jiujiang City

[Objective] The aim was to explore occurrence rules and forecast methods of cotton aphid in Poyang Lake Area in Jiujiang City to enrich prediction methods of cotton aphid in the area. [Method] The occurrence rules and influencing factors of cotton aphid in Pengze County in 28 years were analyzed with comparative analysis, correlation analysis and wavelet analysis. Furthermore, a long-term forecast model of occurrence grade of cotton aphid and a short-term forecast model of weather condi- tion suitability were established based on stepwise regression. In addition, a forecast test was conducted in cotton area in the north of Poyang Lake. [Result] The wavelet analysis showed that in recent 28 years, oscillating period at 4 years was significant for the occurrence grade of cotton aphid in the north of Poyang Lake, but insignifi- cant for cotton at seedling stage. The comparative and correlation analyses suggest- ed that occurrence of cotton aphid is of significant correlation with winter climate and weather conditions at middle and short periods. The prediction test indicated that long-term forecast model of occurrence grade of cotton aphid and short-term forecast model of weather condition suitability based on stepwise regression can be made use of in the areas with similar climate. [Conclusion] The research provides theoreti- cal references for prevention against cotton aphid in cotton-planting area.

Cloning of Partial Sodium Channel Gene From Strains of Fenvalerate-Resistant and Susceptible Cotton Aphid(Aphis gossypii Glover)

The strain of fenvalerate-resistant cotton aphids was selected using fenvalerate insecticide in the laboratory, the resistance factor of the strain was 199.54. Three degenerate primers were designed and used to perform PCR amplification. A cDNA encoding partial sodium channel gene was cloned from the fenvalerate-resistant and -susceptible strains. There were two nucleotide acid differences between fenvalerate-resistant strain and -susceptible strain, resulting in an amino acid mutation, Met→Leu. It is predicted that the mutation is related to the cotton aphid resistance to fenvalerate.

Energy Metabolism Pattern in Cotton Aphid, Aphis gossypii Glover （Hem.： Aphididae） Exposure to Neonicotinoids

This study was mainly made on the role of energy revisers in cotton aphid, Aphis gossypii Glover （Hemiptera： Aphididae） countered with imidacloprid and thiametoxam. We measured used energy, available energy and the content of total energy in three strains of cotton aphid which were from very resistant to neonicotinoid, sup to semi-sensitive and sensitive speccies, respectively. It was observed changes in energy resources rate in all of the aphid strains at which each substrate was metabolized under stress. Our findings indicated among energy sources, total lipid in susceptible strain was increased in counter of spraying and it was decreased in resistance and semi sensitive strains. Whereas, total protein was decreased in all of the strains encountering with neonicotiniod stress. Total glycogen was increased significantly in different aphid strains and sugar was decreased in countered of spraying.

Energy Intensity and Fitness Cost of Cotton aphid Exposure to Neonicotinoids

Three populations of Aphis gossypii of distinct susceptibility to neonicotinoids show differences in the accumulation and mobilization of energy reserves, what may allow the production of their defensive tools against two neonicotinoid insecticides without impairing their reproductive performance. Bioassays were also carried out for these aphid populations. According to the results obtained, the Ag-R population showed resistant rate significantly higher than the other two populations. Levels of some biochemical characteristics were determined in the resistant, susceptible and semi susceptible populations of cotton aphid. The results obtained in the assays with biochemical parameters indicated significant differences in activity among the populations, with higher activity in using glycogen in the Ag-R population. The inverse activity trends oft （generation time） and DT （doubling time） in both resistant and susceptible populations, one showing fitness disadvantage without insecticide exposure and the other not showing it, may underlay the mitigation of insecticide resistance physiological costs observed in the Ag-R population.

Demographic parameters of cotton aphid, Aphis gossypii Glover （Homoptera： Aphididae） on five cotton cultivars

Life table parameters of the cotton aphid, Aphis gossypii Glover, were estimated on five cotton cultivars （‘ Sealand＇ ,‘Siokra＇ ,＇ Vararnin＇ ,‘ Bakhtegan＇ and ‘ Sahel＇ ）. Demographic parameters of the cotton aphid were assessed at 27.5 ± 1 ℃, 65% ＋ 10% RH and a photoperiod of 14：10 （L： D）h. The shortest developmental time for the nymphal stages was 5.5 days on ‘Siokra＇ and the longest was 6.1 days on‘ Sealand＇. The highest offspring per female was 29.6 on ‘Sahel＇ and the lowest was 15.3 on ‘Sealand＇. The rm values varied from 0.272 on ‘Sealand＇ to 0.382 （day^-1） on ‘Varamin＇. Jackknife estimates of the A. gossypii parameters on these cultivars indicated the greatest developmental rate and fecundity on ‘ Varamin＇ and the poorest on ‘ Sealand＇ cultivar.

Global attractivity of the predator-prey system for cotton aphid and seven-spot ladybird beetle with stage structure

It is well known that the cotton aphid is the major pest in cotton fields of Northwest China, and seven-spot ladybird is an important natural enemy among the various possi- ble natural enemies of cotton aphid. In order to increase the applications of population dynamics in integrated pest management and control the cotton aphids biologically, we need to understand the population dynamics of cotton aphid and their natural enemies. A delay predator prey system on cotton aphid and seven-spot ladybird beetle are pro- posed in this paper. Based on the comparison theorem and an iterative method, we investigate the global attra^tivity of the equilibrium points which have important bio- logical meanings. Furthermore, some numerical simulations were carried out to illustrateand expand our theoretical results, in which a conjecture to generalize the well-known Theorem 16.4 in H. R. Thiemes book was put forward, which was taken as the open problem. The numerical simulations show coexistence of periodic solution, confirming the theoretical prediction.

Biological mechanism of controlling cotton aphid (Homoptera: aphididae) by the marginal alfalfa zone surrounding cotton field

At the beginning stage of cotton aphids (Aphis gossypii Glover) invading the cotton field, large numbers of insects have accumulated in the marginal alfalfa (Medicago sativa L.) zone surrounding it. They are 6.94 times (excluded natural enemies) as many as the aphids in cotton field. Most of these insects are Therioaphid maculata (Buckton), and occur in fields 10-15 d earlier than cotton aphids. Consequently, abundant natural enemies have bred in alfalfa zone when cotton aphids increase rapidly in cotton fields in the middle of June in Xinhe County, Xinjiang Autonomous Region. The total number of the major natural enemies, including Coccinellids, Chrysopids and Syphid flies in alfalfa zone, is 13.65 times that in cotton field within the same acreage of fields. At this period, it is very effective to force the natural enemies from the alfalfa zone into the nearby cotton field to control the rapid increase of cotton aphid population by cutting the alfalfa stands.

The biotypes and host shifts of cotton-melon aphids Aphis gossypii in northern China

Aphis gossypfi is a globally distributed species and therefore has a highly variable life cycle. Populations of A. gossypii in northern China exhibit greater genotypic diversity and a broader host range, yet the details of life cycles of different biotypes is still unclear. In this study, the Cytb and 16S gene regions of A. gossypfi collected from 5 common summer hosts and 4 primary hosts were analyzed. A total of 57 haplotypes were obtained from 1 046 individual A. gossyp# sequences. The sequence included 44 variable sites, 27 of which were parsimony informative sites and 17 of which were singleton variable sites. The most frequent 3 haplotypes were found in 896 individuals, representing a total of 85.7% of all individuals and 36 haplotypes were found in 1 individual. A neighbor-joining tree was constructed using 21 haplotypes that were found in more than 2 individuals. Considering the individual host plant, 5 biotypes were identified. Type 1 corresponded exactly to the cucurbit host-race and the other 4 biotypes were found as cotton host-races. Type 3 was the most abundant biotype in cotton fields in northern China.

Insights into wing dimorphism in worldwide agricultural pest and hostalternating aphid Aphis gossypii

Background:The worldwide pest Aphis gossypii has three-winged morphs in its life cycle,namely,winged parthenogenetic female(WPF),winged gynopara(GP),and winged male,which are all produced by a wingless parthenogenetic female(WLPF).Most studies on A.gossypii have focused on WPF,while few have investigated GP and male.The shared molecular mechanism underlying the wing differentiation in the three wing morphs of A.gossypii remains unknown.The wing differentiation of WPF was explored in a previous study.Herein,GP and male were induced indoors.The characters of the body,internal genitals,wing veins,and fecundity of GP and male were compared with those of WPF or WLPF.Compared with WLPF,the shared and separate differentially expressed genes(DEGs)were identified in these three-wing morphs.Results:Newly-born nymphs reared in short photoperiod condition(8 L:16D,18°C)exclusively produced gynoparae(GPe)and males in adulthood successively,in which the sex ratio was GP biased.A total of 14 GPe and 9 males were produced by one mother aphid.Compared with WLPF,the three-wing morphs exhibited similar morphology and wing vein patterns but were obviously discriminated in the length of fore-and underwings,reproductive system,and fecundity.A total of 37090 annotated unigenes were obtained from libraries constructed using the four morphs via RNA sequencing(RNA-Seq).In addition,10867 and 19334 DEGs were identified in the pairwise comparison of GP versus WLPF and male versus WLPF,respectively.Compared with WLPF,the winged morphs demonstrated 2335 shared DEGs(1658 upregulated and 677 downregulated).The 1658 shared upregulated DEGs were enriched in multiple signaling pathways,including insulin,FoxO,MAPK,starch and sucrose metabolism,fatty acid biosynthesis,and degradation,suggesting their key roles in the regulation of wing plasticity in the cotton aphid.Forty-four genes that spanned the range of differential expression were chosen to validate statistical analysis based on RNA-Seq through the reverse transcription quantitative real time polymerase chain reaction(RT-qPCR).The comparison concurred with the expression pattern(either up-or downregulated)and supported the accuracy and reliability of RNA-Seq.Finally,the potential roles of DEGs related to the insulin signaling pathway in wing dimorphism were discussed in the cotton aphid.Conclusions:The present study established an efficiently standardized protocol for GP and male induction in cotton aphid by transferring newly-born nymphs to short photoperiod conditions(8 L:16D,18°C).The external morphological characters,especially wing vein patterns,were similar among WPFs,GPe,and males.However,their reproductive organs were strikingly different.Compared with WLPF,shared(2335)and exclusively(1470 in WLPF,2419 in GP,10774 male)expressed genes were identified in the three-wing morphs through RNA-Seq,and several signaling pathways that are potentially involved in their wing differentiation were obtained,including insulin signaling,starch and sucrose metabolism.

Weed and insect control affected by mixing insecticides with glyphosate in cotton

Field studies were conducted in 2012 and 2013 to evaluate weed and insect control efficacy with glyphosate at 1 230 g ai（active ingredient） ha^（-1） and the insecticides acephate（728 g ai ha^（-1））,carbosulfan（135 g ai ha^（-1））,endosulfan（683 g ai ha^（-1））,imidacloprid（32 g ai ha^（-1））,or lambda-cyhalothrin（23 g ai ha^（-1））,as well as glyphosate tank-mixed with these insecticides.Four of the most common weeds in cotton,common purslane,false daisy,goosegrass,and lambsquarters,were manually sown in the cotton field and treated with glyphosate alone or in combination with insecticides.Glyphosate efficacy,based on visual estimates of control and weed fresh weight at 21 d after treatment（DAT）,was unaffected by the addition of insecticides.Four weeds were controlled by 93-97%and 86-100%（visual rating） and reduced weed fresh biomass by98-99%and 96-100%with glyphosate alone and its combination with insecticides,respectively.Addition of glyphosate to acephate improved cotton aphid control compared with acephate alone.However,addition of glyphosate to carbosulfan,endosulfan,imidacloprid,or lambda-cyhalothrin did not affect the aphid control when compared with the insecticide alone treatments.These results indicate that cotton producers could potentially integrate weed and insect management strategies by choosing suitable insecticide mixing partners with glyphosate,thereby reducing the application costs without sacrificing the efficacy of the glyphosate or the insecticides.

棉花凝集素类受体蛋白激酶基因GhLecRK1响应棉蚜危害的功能分析

【目的】克隆棉花(Gossgpium hirsutum)凝集素类受体蛋白激酶(LecRK1)基因GhLecRK1,分析其在响应棉蚜危害中的功能,为培育棉花抗蚜新品种提供理论参考。【方法】在棉蚜诱导的棉花叶片全转录组测序数据分析基础上,克隆响应棉蚜危害的GhLecRK1基因,并对其序列进行生物信息学分析。采用实时荧光定量PCR检测GhLecRK1基因在棉蚜诱导下的表达模式,运用瞬时过表达技术研究其在棉花对棉蚜防御响应中的功能。【结果】GhLecRK1基因开放阅读框(ORF)长度1233 bp,编码410个氨基酸残基,理论等电点(pI)8.36,预测蛋白质分子量45948 Da,由具有1个α-甘露糖凝集素结合结构域、1个S-糖蛋白结构域(SLG)和1个纤溶酶原/苹果/线虫结构域(PAN)组成,属G型凝集素类受体蛋白激酶。同源序列比对分析结果表明,GhLecRK1与其他植物的G型LecRLKs序列具有高度相似性(94.39%)。系统发育分析结果表明,GhLecRK1与Gossypium raimondii的Gr012449778.1亲缘关系最近。在棉蚜取食诱导后24、48和72 h的棉花植株的子叶、根、茎中GhLecRK1基因的表达量均有不同程度上调,但是仅有子叶在棉蚜取食24 h时GhLecRK1基因相对表达量显著上调(P<0.05,下同)。选择性和非选择性试验结果显示,瞬时过表达GhLecRK1基因棉花上棉蚜的数量均少于WT植株和pMD植株,且在取食48 h时过表达GhLecRK1基因棉花上棉蚜蜜露的分泌量显著减少。【结论】GhLecRK1基因响应棉花对棉蚜的防御反应,GhLecRK1基因过量表达后可增强棉花对棉蚜的抗性。

棉蚜虫情信息监测研究进展

棉花是我国重要的战略物资,也是我国重要的经济作物之一,对我国的农业生产、民生生活、二三产业具有重要作用。棉蚜是棉花生长发育进程中主要的害虫之一,棉蚜虫情信息获取的滞后性、不准确性将导致生产上农药的过度施用,进而加速棉花生境破坏和棉田环境污染。因此,实时、精准地获取棉田棉蚜虫情的时空分布、危害等级、发生面积等信息,对棉蚜的防治、棉田管理、农田环境保护等具有重要现实意义。遥感技术、机器视觉技术加快了棉田棉蚜虫情的实时、动态信息的获取和虫情等级的判别。聚焦“棉蚜虫情信息监测”,开展了国内外文献查阅与梳理,分别阐述了传统方法、遥感技术和图像识别对棉蚜虫情信息的研究现状与进展。探讨了棉蚜监测存在的问题,对未来棉蚜危害信息的监测与诊断研究重点和发展趋势进行了展望。

2种蚜虫取食诱导棉花对棉长管蚜与棉蚜取食行为的影响

为研究棉长管蚜Acyrthosiphon gossypii与棉蚜Aphis gossypii对蚜虫取食诱导棉花的取食适应性,揭示取食诱导下两种蚜虫的取食竞争机制,采用刺探电位图谱技术(electrical penetration graph, EPG)测定在健康棉花、棉长管蚜或棉蚜诱导的棉花上取食6 h的棉长管蚜和棉蚜的16个重要参数,比较两种蚜虫的取食行为。研究发现:1)取食健康棉花时,棉蚜在木质部(G波)的取食持续总时间长于棉长管蚜,棉蚜在木质部的取食能力大于棉长管蚜,但二者在韧皮部的取食能力相差不大。2)取食棉长管蚜诱导的棉花时,棉蚜取食韧皮部(E2波)持续的总时间为(2 531.33±60.86)s,显著大于棉长管蚜E2波持续总时间[(2 196.00±98.91)s];取食棉蚜诱导的棉花时,棉蚜取食韧皮部、木质部持续的总时间显著长于棉长管蚜(P<0.05),说明棉蚜对于棉蚜诱导棉花的取食耐受性大于棉长管蚜。棉蚜对两种蚜虫取食诱导棉花的适应性更强,更易在竞争中取得优势。棉长管蚜与棉蚜取食棉长管蚜或棉蚜诱导棉花的F波持续总时间长于健康棉花,说明经取食诱导的棉花具有一定的抗虫性。

棉花蚜虫防治药剂筛选

[目的]有效防治棉花蚜虫虫害。[方法]选择5种常用杀虫剂,在棉花苗期,采用叶面喷施的方法,进行田间防效比较。[结果]通过比较不同药剂的防治效果,25%高效氯氟氰菊酯·啶虫脒乳油225 g/hm2效果最好,防效可达96%以上。[结论] 25%高效氯氟氰菊酯·啶虫脒乳油的防效明显高于另外4种药剂,可在棉花生产中推广应用。

不同寄主植物与棉蚜酯酶活性的关系

通过测定不同越冬寄主植物棉蚜Aphisgossypii种群α 乙酸萘酯 (α NA)酯酶的活力 ,结果表明 :山东高密棉田棉蚜种群酯酶活力是北京花椒棉蚜酯酶活力的 2 4倍 ,石榴、木槿上棉蚜酯酶活力是花椒棉蚜酯酶活力的 1 3～ 1 5倍。不同寄主植物棉蚜α NA酯酶和 β NA酯酶的频率分布表明 :鼠李、花椒棉蚜的α NA酯酶频率分布范围较集中 ,酯酶活力 (每 0 0 33头蚜虫的OD值 )小于 0 10时的频率分别为 70 %和 62 % ,其个体累积率达 50 %时的酯酶活性 (EF50 )分别为 0 0 8和 0 0 85(每 0 0 33头蚜虫的OD值 ) ;石榴、木槿和棉苗上α NA酯酶频率分别为 2 5%、 31%和4 5% ,其EF50 分别为 0 154、 0 1368和 0 1138,酯酶活力明显比鼠李和花椒棉蚜高 ;高密棉蚜为4 % ,EF50 为 0 2 113,频率分布范围较宽。β NA酯酶的频率分布 ,鼠李、花椒、木槿和棉苗上棉蚜酯酶活力 (每 0 0 33头蚜虫的OD值 )小于 0 10时为 52 %～ 62 %的个体 ,EF50 分别为 0 0 98、0 0 84、 0 10 2和 0 0 91,寄主之间差异不大 ,而石榴和高密棉蚜分别为 2 3%和 3% ,EF50 分别为0 135和 0 2 136,与其它

不同地理种群棉蚜对温度和光周期的生态适应性

实验室研究了采自越南胡志明市、我国海南三亚市、北京市和新疆石河子市 4个棉蚜地理种群对温度和光周期的适应性分化特征。在 1 8℃配合光周期 L:D=8:1 6和 L:D=1 0 :1 4的条件下 ,越南和中国海南种群无性蚜分化现象 ,而北京和新疆种群则产生大量性蚜并产下受精卵 ,表明短光照已不能诱导低纬度热带地区种群产生性蚜。应用实验种群生命表技术研究了 3 5℃、3 0℃、2 5℃、2 0℃、1 5℃五个温度下新疆种群、北京种群和越南种群的存活、生长发育、繁殖及内禀增长率的差异 ,结果表明 ,在 2 0℃～ 3 0℃的温度区间内 ,各种群间生命参数差异不显著 ,而在低温下 (1 5℃ ) ,差异则比较显著 ,成蚜寿命和产蚜量均为新疆种群 >北京种群 >越南种群 ,表现为高纬度种群大于低纬度种群 ,其内禀增长率也随纬度升高逐渐增大 ,而来自热带地区的越南种群对高温则比较适应 ,其在 3

蚜虫胁迫下棉叶光谱特征及其遥感估测

在棉蚜危害棉花的主要生育期测试蚜害后不同严重度叶片的理化参数和光谱,分析并比较了不同时期、不同品种蚜害棉叶理化参数和光谱反射率特征,确定了蚜害棉叶光谱敏感波段,建立了蚜害棉叶严重度估测模型。结果表明:蚜害棉叶的理化参数和光谱特征明显,蚜害棉叶平均厚度,含水量,温度和叶片CHL.b均增加,叶片而平均CHL.a,CHL.a+b和Cars含量减少。不同时期、不同品种蚜害棉叶光谱反射率在可见光均表现先升后降的特征,但不同品种蚜害棉叶在近红外波段反射率不同。434～727和648nm可分别作为蚜害棉叶的光谱敏感波段和最佳波段。基于敏感波段建立的蚜害棉叶遥感估测模型均达到显著相关,其中以(R1589-R648)/(R1589+R648)为自变量建立的估算模型精度最高,相对误差最小(0.128),可作为蚜害棉叶严重度最佳识别模型。该研究为遥感大面积监测棉花蚜虫提供了理论依据及参考。

河北省不同地区棉蚜对吡虫啉等杀虫剂抗药性发展动态研究

2004—2007年间,测定了氧化乐果、灭多威、吡虫啉和啶虫脒等杀虫剂对河北省不同地区棉蚜的毒力。与敏感基线比较,河北省各地棉蚜对灭多威的抗药性始终处于中、高抗水平,抗性倍数最高达94.04倍;对氧化乐果的抗药性发展较快,但基本仍处于中、低抗水平,其抗性倍数为2.15～20.76;河北省各地棉蚜种群对新烟碱类杀虫剂吡虫啉和啶虫脒的抗药性差异波动较大,对啶虫脒的差异最大可达25.83倍。

转Cry1A基因棉对棉蚜生长发育及种群动态的影响

棉蚜 (AphisgossypiiGlover)是棉花的重要害虫之一。为了明确长江中游棉区Bt棉花对棉蚜发生的影响 ,笔者在实验室和田间研究了Bt棉花棉蚜的发生规律。实验室棉蚜种群生命表的研究表明 ,取食Bt棉花GK19、BG1560和普通棉花泗棉 3号棉蚜的生命参数无显著差别。 2 0 0 1～ 2 0 0 2年在湖北省天门市的大田研究表明 ,Bt棉GK19、BG1560和未施药泗棉