Spatial Distribution Pattern and Application of Fourth-Generation Mature Larvae of Cotton Bollworm(Helicoverpa armigera Hübner) in Corn Field

[ Objective] The paper was to study the spatial distribution pattern of fourth-generation mature larvae of cotton bellworm in corn field. [ Method] The plots with different occurrence densities of fourth-generation cotton bollworm were investigated from August to September in 2009. Six groups of sampling data were obtained, and seven indicators including aggregation index method, Iwao method and Taylor method, etc. were used to determine its spatial distribution pattern. [ Result ] Aggregation index test showed that in all plots, Moore I 〈 0, Lloyed m＊/m 〈 1, Kuno Ca 〈 0, diffusion coefficient C 〈 1, diffusion index 16 〈 1, negative binomial distribution K 〈 0, indicating that mature larvae of cotton bollworm showed uniform distribution in summer corn. Iwae regression equation of fourth-genera- tion mature larvae of cotton boUworm in summer corn was m ＊ = 0. 090 6 ＋ 0. 766 9 m, r = 0. 986 3, indicating that the basic components of cotton bollworm distribu- ted was single individual, and mature larvae of cotton bollworm in summer corn showed uniform distribution. The optimal sampling number of fourth-generation ma- ture larvae of cotton bollworm in corn under different population densities could be calculated using formula N1 = （ 1. 090 6/m -0. 233 1 ）/D2. [ Conclusion] The result provided basis for accurate evaluation of population quantities and variation law of cotton boUworm, as well as prediction and control of the pest.

Studies on the Relationship between Occurrence Degree of Cotton Bollworm and Rainfall

[ Objective ] The aim of the study is to investigate the factors causing the outbreak of cotton bollworm and to provide effective measures for controlling cotton bollworm. [ Method] Based on the analysis of the data about insect and weather situation in Luyi County in 32 years, the meteorological, prediction model was established for monitoring the quarterly or monthly occurrence trend of cotton bollworm. [Result] The cotton boillworm occurred slightly in the years with rainfalls of 3 months over 500 nm and severely in the years with rainfalls of 3 months： less than 400 rim. The results of correlation analysis show that annual occurrence degrees of cotton bollworm and occurrence degrees of 4^th generation of cotton bollworm are extremely negatively correlated with rainfall during June - August; the occurrence degrees of 3^rd and 4^th generations of cotton bollworm are also extremely negatively correlated with rainfall in July. [ Conclusion] The occurrence of cotton bollworm in field is heavily influenced by rainfall in at its occurrence stage; moreover, the rainfall during June - August is the decisive factors influencing the occurrence of cotton bollworm.

Performances of the cotton bollworm,Heliothis armigera (Hubner) at different temperatures and relative humidities

The cotton bollworm, Heliothis armigera (Hubner) is an important insect species at-tacking many crops. Their performances have been examined at temperatures from 15℃ to 35℃ and relative humidities (RH) between 22.5% and 100%, respectively, in order to assess possible effect of climate in future on its occurrence and infestation. Durations of all developmental stages of the insect shortened with increasing temperature. The temperature favoring population growth ranged from 25℃ to 30℃.Larval duration and adult longevity decreased as relative humidity increased, but development of other stages was independent of RH. At RH of over 64%, their survival rate, egg production and oviposition rate varied a little, and all the population parameters of the insect remained at a relative constant level.

Efficiency of cotton bollworm (Helicoverpa armigera Hübner) control of different Bt cotton varieties in North China

Background： The cotton bollworm （Helicoverpa armigera） is one of cotton＇s most destructive insect pests in terms of yield and quality. Since 1997, China has grown commercially available transgenic Bacillus thuringiensis （Bt） cotton. We aimed to investigate the variation in resistance of transgenic Bt cotton varieties to cotton bollworm in North China. Methods： Populations of cotton bollworm were monitored from 2008 to 2015 in environments where Bt cotton was planted adjacent to other non Bt crops. The study included 197 Bt cotton varieties planted in 42 counties/locations in three provinces （Hebei, Shandong and Henan） of North China, which were evaluated through field investigations, bioassays, and enzyme linked immunosorbent assays （ELISA）. Results： The average number of cotton bollworms never exceeded the action threshold （10 larvae per 100 cotton plants）, however, their number reached 19.55 per 100 cotton plants in 2011. The ratios of damaged plants to total Bt cotton stem tips, buds, and bolls was low except in 2010, when the ratios reached 1.82%, 2.09%, and 10.63%, respectively. The results of bioassay showed that the corrected mortality were higher at the second generation cotton bollworm stage than the third and fourth germination stages. Totally, Bt protein content declined sharply at the seedling stage from 2008 to 2015. Conclusions： This study indicated that almost all Bt cotton varieties were capable to effectively control the populations of cotton bollworm in North China.

THE FUNDAMENTAL STRATEGY FOR THE CONTROL OF COTTON BOLLWORM OUTBREAKS IN CHINA

on the basis of the analysis of the factors causing the cotton bollworm outbreaks and control failure, the authors recommend that the fundamental strategy for solving the problem of cotton bollworms in China should be to conduct area-wide unified controls rather than depend on insecticides. The unified control system is the guarantee for Integrated Pest Management (IPM) for small-scale crop owners at present. So the authors call on policymakers to put stress on organizing individual growers to carry out area wide unified controls.

Determining the major Bt refuge crops for cotton bollworm in North China

Evaluation of the effectiveness of refuge strategies involved in cotton boll- worm Bt resistance management would be aided by technologies that allow monitoring and quantification of key factors that affect the process under field conditions. We hy- pothesized that characterization of stable carbon and nitrogen isotopes in adult bollworm, Helicoverpa armigera （Htibner） （Lepidoptera： Noctuidae） moths may aid in determining the larval host that they developed upon. We found moths reared from larvae fed on peanut, soybean or cotton, respectively, could be differentiated using isotopic analyses that also corresponded to their respective larval host origins. These techniques were then used to classify feral second-generation bollworm moths caught in Bt cotton （Gossypium hirsu- rum） fields into different populations based on their isotopic signatures. In 2006-2007 feral moths captured in Bt cotton fields predominantly correlated with the peanut （Arachis hypogea） having served as their larval host, indicating this is the most important refuge crop for Bt-susceptible bollworm individuals （providing 58%-64% individuals） during independent moth peaks for the second generation in North China. The remaining feral moths correlated with soybean （Glycine max） （0-10%）; other C3 plant （20%-22%） and non-C3 plant （12%-14%） host types also provided some Bt-sensitive moths. Field obser- vations showed that peanut constitutes the primary refuge crop contributing to sustaining Bt-susceptible moths dispersing into cotton in North China. These results suggest that peanut may be a more effective refuge to sustain Bt-susceptible bollworm individuals and reduce the risk of development of a Bt-resistant biotype.

Expression of two insect-resistant genes cryIA (b&c)/GNA in transgenic tobacco plants results in added protection against both cotton bollworm and aphids

The synthesized Bacillus thuringiensis insecticidal protein gene crylA(b&c) and the synthesized gene GNA, (the mannose specific lectin from snowdrop ( Galanthus nivalis)), tumefaciens have been inserted into plant expression vector pGW4BAI. Leave stripes of Nico-tiana tabacum var. K326 have been transformed with Agrobacterium tumefaciens strain LBA4404 harboring the plant expression vector. 28 kanamycin resistant tobacco plants

Transgenic tobacco plants expressing synthetic Cry1Ac and Cry1Ie genes are more toxic to cotton bollworm than those containing one gene

Transgenic tobacco plants carrying Cry1Ac, Cry1Ie or both genes were obtained. In the leaves of transgenic plants carrying both genes, the contents of Cry1Ac and Cry1Ie proteins were 0.173% and 0.131% of the total proteins, respectively. Cry1Ac protein content was 0.182% and Cry1Ie protein con- tent was 0.124% of the total proteins in the leaves of transgenic plants containing only one Bt gene. Fresh leaves of transgenic tobacco and wild-type plants were used for the insect bioassay against wild-type and Cry1Ac-resistant cotton bollworm (Helicoverpa armigera). The bioassay results showed that transgenic plants carrying both genes were significantly more toxic to wild-type and Cry1Ac-resistant cotton bollworm than those carrying Cry1Ac or Cry1Ie alone. This study indicates that the higher toxicity of transgenic tobacco plants carrying both genes is caused by the cooperative function of both Bt proteins, thus providing a potential way to delay the development of insect resis- tance to transgenic crops.

Combining Ability and Heterosis Between High Strength Lines and Transgenic Bt (Bacillus thuringiensis) Bollworm-Resistant Lines in Upland Cotton (Gossypium hirsutum L.)

To analyse the combining ability and heterosis between high-strength lines and transgenic Bt bollworm-resistant lines in upland cotton, 5 high-strength lines were crossed as female lines with 12 transgenic Bt bollworm-resistant lines according to NCII design. It was demonstrated that the compositions of variance in various traits were quite different. For seed cotton yield, lint yield, boll numbers per plant and boll weight, the dominant (special combining ability) effects were the major effects, accounting for 87.38, 84. 40, 80. 04 and 64. 46% of the total phenotypic variances, respectively, while for fibre strength and micronaire value, the additive (general combining ability) effects had the major effects, with a ratio of additive variance to phenotypic variance of 78.85 and 43.80%. As for lint percent and 2.5% span length, the dominant and additive variances had similar effects, in phenotypic variances (54.94 and 40.11% for lint percent, 45.76 and 42.49% for 2. 5% span length, respectively). The mid-parent heterosis (Hpm), surpassing parent heterosis (Hpb) and competitive heterosis (Hck) for seed cotton yield and lint yield were both extremely significant. For fibre properties, the Hck and Hpm of 2.5 % fibre span length were extremely significant, the Hck of fibre strength was significant, and the favorable negative Hck of micronaire was also extremely significant. The increments of hybrid over common variety were 17% for lint yield and fibre strength, 7% for fibre span length, and 4 % for fineness.

棉铃虫发生发展与气候条件的关系研究进展

棉铃虫(Helicoverpa armigera)属鳞翅目夜蛾科,是一种世界性的害虫,在世界各地均有分布。因其具有远距离迁飞,繁殖力强等特点,条件适宜时常大面积暴发成灾,给农业生产带来较大损失。摸清棉铃虫生活习性、种群变化规律是棉铃虫防治的前提条件。由于棉铃虫是变温昆虫,气候条件对其生长发育、成灾机制等产生极大影响。因此,本文系统综述了气候变暖对棉铃虫影响的研究进展,包括棉铃虫生长发育、体色变化、繁殖、滞育、飞行、越冬、与作物的互作关系等方面,并对未来研究重点进行了展望。

Selection of Homozygous Cotton Lines Transformed with Two Insect-Resistant Genes

A plant expression vector containing a chimeric Bt29K gene coding for the activated Cry1Ac protein and the arrowhead proteinase inhibitior gene API B were introduced into the cotton cultivar Jihe321 mediated by Agrobactertium tumefaciens. Based on the results of kanamycin resistant testing, PCR detection for both foreign genes and insect bioassay using Heliethis armigera , nine transgenic homozygous cotton lines with insect resistance of more than 90% and better agronomic traits were bred through six generations from the original transgenic plants. Results from insect bioassay and sequence analysis of the PCR products of plants from some homozygous lines indicated that the chimeric Bt29K gene was stably inherited in these transgenic cotton lines. The main agronomic characters of these homozygous cotton lines, such as boll productivity and fibre strength, were better than that of the original cotton cv. Jihe321.

Impact Analysis of Genetically Modified (Bt) Cotton Genotypes on Economically Important Natural Enemies under Field Conditions

Field studies were conducted at Hisar during Kharif, 2009-2010 and 2010-2011 under natural and unsprayed condition. RCH 134 Bt, HS 6 (non Bt), H 1117 and Ganganagar Ageti (non Bt) were selected for the studies. The experiment was laid down in Randomized Block Design replicated thrice having plant spacing 67.5 × 60 cm. Among the bollworms, Erias spp. exhibited positive correlation with rainfall, minimum temperature and relative humidity morning hours significantly at 5 percent level whereas Helicoverpa and Pectinophora displayed positive relations only with evening hours relative humidity significantly while Spodoptera were significantly positive correlated with relative humidity of morning and evening hours. Bollworm complex was negatively correlated with all the weather parameters employed to study although being non-significant in case of rainfall, maximum and minimum of temperature, morning and evening hours of relative humidity. Among the sucking pests, leafhoppers, whitefly, thrips and aphids population showed significantly negative correlation with weather parameters. The comparison of natural bio-agents in cotton hybrids under study revealed that overall mean population of natural enemies were higher in Bt cotton hybrid as compared to non-Bt. These results confirm that use of genetically modified (Bt) cotton in lieu of conventional genotypes could positively impact non-target and beneficial insect species by preserving their host populations.

棉铃虫室内继代饲养常见问题及对策

棉铃虫是一种危害较大的农业害虫,同时也是教学和科研中常用的实验昆虫。人工饲养过程中常因管理操作不当,使种群难以为继。本文根据多年实验室饲养棉铃虫经验,分析了继代饲养过程中常出现的问题及对策,以期为棉铃虫室内继代饲养提供参考。

河西地区玉米田棉铃虫对2种Bt蛋白的敏感性监测

【目的】明确河西走廊棉铃虫对玉米Bt蛋白的敏感性,为科学监测棉铃虫的发生危害规律提供科学依据。【方法】饲料表面覆盖毒素法测定了河西走廊嘉峪关(JYG)、酒泉(JQ)、张掖(ZY)、武威(WW)4个棉铃虫地理种群对Cry1Ab和Cry1Ac蛋白的敏感性,计算LC_(50)和LC_(99).【结果】JYG、JQ、ZY和WW种群对Cry1Ab的LC_(50)分别为0.1162、0.1460、0.1721、0.2004μg/cm^(2),LC_(99)分别为7.2778、6.0807、97.0666和27.1037μg/cm^(2);JYG、JQ、ZY和WW地理种群对Cry1Ac的LC_(50)分别为0.1050、0.2554、0.0172和0.0456μg/cm^(2),LC_(99)分别为0.1598、11.7953、1.1904、7.4709μg/cm^(2),其中JQ地理种群对Cry1Ac的LC_(50)值显著高于其他地理种群.【结论】河西走廊玉米棉铃虫对Cry1Ab和Cry1Ac蛋白的敏感性较高,暂未对Cry1Ab和Cry1Ac蛋白产生抗性。但应该持续加强监测,以避免Bt交互抗性产生应用风险.

BIONOMIC OF CAMPOLETIS CHLORIDEAE (HYM:ICHNEUMONIDAE)AS A PARASITOID OF THE COTTON BOLLWORM HELICOVERPA ARMIGERA (LEP:NOCTUIDAE) *

The bionomics of Campoletis chlorideae and the regularity of its seasonal fluctuations were studied in Changsha district,Hunan province. Field investigation indicated that there were ten generations of C. chlorideae a year, of which seven occurred in cotton fields. Three peaks of cotton bollworm parasitization by C. chlorideae were observed, early May to late June, mid August to early September, mid September to mid October respectively. One peak occurred in tomato and tobacco fields, the other two in cotton fields. The parasitization rate ranged from 25.1%- 63.1%. The total development time from egg to adult ranged from 13.0 days at 32℃ to 75.5 days at 11.6℃. Each wasp could parasitize the 5-23 second instar larvae of tobacco caterpillar. C. chlorideae could parasitize the cotton bollworm, beet armyworm and tobacco caterpillar, but preferred the cotton bollworm larvae. C. chlorideae could parasitized 1st-3rd instar larvae of the tobacco caterpillar, but seldom parasitzed 4th-6th instar larvae. Moreover, C. chlorideae preferred second instar larvae. Theoretical models for developmental speed, adult longevity and the influence of temperature were proposed. The overwintering of C. chlorideae Uchida was also discussed. Moreover, methods for utilization of C. chlorideae Uchida in crop protection were presented and the bionomics of Campoletis chlorideae in both the Yangtze River Valley and Yellow River Valley were compared.

转基因棉Bt毒性表达的时空动态及对棉铃虫生存、繁殖的影响

转Ｂｔ基因棉３１０品系在不同发育阶段，对棉铃虫的毒性表达测定表明，（１）棉株各空间组织在不同发育阶段均能强力阻止棉铃虫取食，表达出较高的抗虫效果。（２）棉株不同空间组织在同一时期，毒性表达存在差异，以营养组织，中、小蕾高于大蕾和铃。（３）同一组织毒性表达随着棉株生长、发育、成熟、衰老逐渐呈动态下降。（４）前后各阶段，同一组织饲喂棉铃虫，死亡所需要天数呈动态增加，但最终生存率降低到一个较低水平。存活老熟幼虫重量、蛹重及蛹羽化率比对照棉铃虫下降３０％～５０％，羽化的蛾子进行自交或异交均能产下受精率、孵化率很高的卵。取食Ｂｔ转基因棉的雌蛾产卵量比对照减少５０％～７０％。

转基因抗虫棉的抗性鉴定

１９９４～１９９５年采用棉铃虫初孵幼虫鉴定Ｒ１、Ｒ２、Ｒ３代Ｂｔ转基因棉花２０００多株次，筛选出Ｒ１代抗虫效果达８０％以上的单株１１个，占参测株６．２１％；Ｒ２代（株系）１５个，占参测株系１３．８９％；Ｒ３代３７５株，占参测株７１．２９％。１２份材料进入复鉴，８份材料在罩笼接虫中，百株活虫数及被害蕾铃率平均比对照分别减少８８％～１００％及９０％～１００％；叶、蕾饲喂棉铃虫３龄幼虫，毒性效果均在８０％以上，３龄棉铃虫幼虫取食抗虫棉后，取食量、排泄量及体长和体重增长率比对照减少５０％～１０７％，第四天出现死虫，且对红铃虫亦有较强的抗性。

烟青虫和棉铃虫在烟草上的生态位及其种间竞争

通过 2 0 0 0～ 2 0 0 1两年的田间调查和室内饲养 ,测定了烟青虫和棉铃虫在烟草上的生态位和种间竞争系数。结果表明 :棉铃虫在烟草上的时间生态位宽度、生态位重叠均大于烟青虫 ,两者的时间生态位相似性比例为 0 .7342 ;两种害虫的空间生态位宽度、生态位重叠很相近 ,生态位相似性比例高达 0 .85 5 9。烟青虫的竞争系数为 0 .312 2 ,棉铃虫的竞争系数为 1.832 0 ,说明棉铃虫的竞争力大于烟青虫。在烟株同一部位两种害种共存率最高仅有 9.30 %。

螟黄赤眼蜂在棉田的有效扩散距离及其影响因素的研究

１９９４～１９９５年，在山东禹城棉田进行了田间释放螟黄赤眼峰Ｔｒｉｃｈｏｇｒａｍｍａｃｈｉｌｏｎｉｓ试验，结果表明：①螟黄赤眼峰的有效扩散距离与日照时数有关，日照时间越长，有效扩散距离越远；②螟黄赤眼蜂在棉田的群体有效扩散距离与放蜂期间的田间平均气温呈显著正相关，田间气温较高时（＞２４℃），螟黄赤眼蜂可扩散到２５ｍ以远；当田间平均气温较低时（＜２０７℃），使１００％的蜂个体都仅仅分布在距放蜂点２５ｍ的范围内。６～８月份，螟黄赤眼蜂在田间的有效扩散距离为１０～２５ｍ；③降雨可严重抑制赤眼蜂的田间扩散；④湿度与螟黄赤眼蜂在棉田有效扩散距离呈显著负相关，当湿度太大时（相对湿度＞８９％），使螟黄赤眼蜂聚集在放蜂点附近；⑤风速和风向不仅可影响螟黄赤眼蜂的田间有效扩散距离，而且也影响赤眼蜂的田间扩散方向。

新型非甾醇蜕皮激素类杀虫剂对棉铃虫幼虫蜕皮的影响

用透射电镜技术研究了新型非甾醇蜕皮激素类杀虫剂W2 0 0 0 13对棉铃虫 4龄幼虫蜕皮的影响。结果表明W2 0 0 0 13使棉铃虫产生早熟、致死的蜕皮。中毒试虫 6h表现出内表皮层沉积加快 ,皮细胞中粗面型内质网大量增加 ,糖原颗粒减少 ;12h蜕皮间隙开始形成 ,细胞质凝集 ;2 4h新、旧表皮同时存在 ,皮细胞空泡化严重 ;36h新上表皮覆盖于仅沉积几层的新原表皮上 ,旧表皮仍然保持 ,皮细胞呈恶化、降解状态 ,宏观上虫体不表现出蜕皮行为而死亡。而且比较研究可见W2 0 0 0 13在中毒症状、生物测定结果、超微结构水平与RH 5 992具有相似的作用。