向日葵螟幼虫的空间分布型及抽样技术

欧洲向日葵螟Homoeosoma nebulellum Denis et Schiffermüller是向日葵上的主要害虫,本文利用6种聚集指标对向日葵螟幼虫的空间分布型进行了测定,结果表明其呈现聚集分布。样本平均数(m)与方差(S2)的对数值的关系式为:lgS2=lg0.2130+0.5639lgm,显示向日葵螟幼虫的空间分布随密度的升高而趋向均匀分布。Iwao的m*-m回归方程为:m*=8.1177+0.1447m,显示该虫在田间分布的基本成分是个体群,个体间相互吸引,个体群的空间分布型为均匀分布。对聚集原因进行分析,得出λ<2,表明向日葵螟幼虫的聚集是由于环境作用所引起的。用Iwao的理论抽样数模型计算出向日葵螟幼虫的理论抽样数模型为:D=0.1时,n=911.77/m-85.53,D=0.2时,n=227.94/m-21.38。采用m*-m关系的序贯抽样模型制定出食葵田间的序贯抽样模型为:T1(n),T0(n)=7.40n±4.54n,油葵田间的序贯抽样模型为:T1(n),T0(n)=10.05n±2.29n。     

向日葵螟对不同向日葵品种的寄主选择性

通过田间选择性试验结合室内黑色素鉴定,研究向日葵螟Homoeosoma nebulellum Denis et Schiffermüller对35个不同向日葵品种的寄主选择性。向日葵螟对不同供试向日葵品种的选择性存在显著差异,选择性最强的是大黑片,其次是S47,再则是5135和RH316,选择性较弱的有T25和天葵503等18个品种,对TO12244和GT110等13个品种无选择性。寄主选择性可以用开花盛期的花盘被害率、每盘可见幼虫数、每盘虫粪指数与籽粒成熟期的籽粒被害率、籽粒被害虫情指数5个指标中的任何一个来评价。相关性分析表明,向日葵螟的寄主选择性与向日葵花盘直径呈显著正相关关系。     

向日葵螟成虫种群消长动态和空间分布型

为了科学指导应用播期避害、性诱剂诱捕成虫和田间释放天敌昆虫-赤眼蜂防治向日葵螟,确定最佳防治时期和选择最佳防治方法,2009—2011年,在内蒙古巴彦淖尔市利用向日葵螟Homoeosoma nebulellum(Denis et Schiffermüller)性诱剂进行了向日葵螟田间种群动态和空间分布型的研究。结果表明,向日葵螟成虫每年5月中旬始见,直到9月底,一年有两个明显的成虫蛾峰期,第1个蛾峰期出现在6月下旬至7月上旬,第2个蛾峰期在7月下旬至8月中旬,当地向日葵1年受到两代幼虫的危害,而且开花期与向日葵螟两个蛾峰期吻合度越高,向日葵受葵螟幼虫的危害越重;通过应用5种聚集度指数测定和Blackith种群聚集均数λ分析,向日葵螟成虫在田间呈聚集分布,聚集主要由向日葵螟自身行为及环境因素引起。根据成虫动态和空间分布型,可以科学指导应用播期避害、性诱剂诱捕器和释放天敌昆虫的最佳时期及方式。     

内蒙古巴彦淖尔地区向日葵螟的种群动态与生活史

为了制定科学、有效的向日葵螟Homoeosoma nebulellum Denis et Schiffermüller（鳞翅目：螟蛾科）测报和防治对策,通过野外调查和室内饲养观察对内蒙古巴彦淖尔地区向日葵螟的发生为害规律及生活史进行了研究。结果表明：当地向日葵螟的寄主有菊科的向日葵Helianthus annuus L.、茼蒿Chrysanthemum coronarium Mill.、刺儿菜Cephalanoplos segetum（Beg.） Kitam和苣荬菜Sonchus brachyotus DC.,其中苣荬菜作为向日葵螟的寄主在我国是首次报道。应用性信息素监测结合田间调查的结果表明,当地向日葵螟一年发生2代,其中越冬幼虫4月下旬开始化蛹,5月中旬开始羽化,但此时羽化的成虫由于缺乏开花寄主而无法产卵为害。第1代幼虫在6月末为害茼蒿、7月下旬开始为害开花的向日葵。第1代幼虫于7月下旬开始羽化产卵形成第2代,其中有9.2%的老熟幼虫直接滞育越冬。第2代幼虫自8月中旬起为害晚开花的向日葵,9月中旬老熟后陆续入土越冬,至10月上旬收获时仍有30.0%的幼虫未老熟而随收获的葵花盘转至筛选出的杂质中越冬。在24℃,RH 70%和L16∶D8光照条件下测定第2代向日葵螟卵、幼虫和蛹的发育历期分别为4.2、15.9和11.1 d,雌、雄蛾寿命分别为14.9 d和15.1 d.综合观察结果,绘制了巴彦淖尔地区向日葵螟的生活史表。     

向日葵组织培养研究进展

向日葵(Helianthus annuus)是世界主要的油料作物之一.近几年来有关向日葵的研究很多,其中向日葵组织培养研究越来越受到重视.本文从向日葵外植体培养、植株再生影响因素、组培过程中存在的问题及解决方法等方面进行了综述.     

向日葵分子生物学研究进展

向日葵是一种营养价值极高的资源植物,向日葵的研究和生产在当前我国中西部大开发的战略中具有重要的意义。本文对近年来国内外向日葵分子生物学研究的最新进展,在蛋白质、酶、基因及基因工程、分子标记等方面进行了综述。特别对生化标记、分子标记技术在向日葵研究上的应用及所取得的成果作了重点介绍,并对今后向日葵研究工作进行了展望。     

向日葵分子生物学研究进展

向日葵是一种营养价值极高的资源植物,向日葵的研究和生产在当前我国中西部大开发的战略中具有重要的意义。本文对近年来国内外向日葵分子生物学研究的最新进展,在蛋白质、酶、基因及基因工程、分子标记等方面进行了综述。特别对生化标记、分子标记技术在向日葵研究上的应用及所取得的成果作了重点介绍,并对今后向日葵研究工作进行了展望。     

化感植物向日葵叶化学成分的研究

从向日葵(Helianthus annuus L.)叶子的甲醇提取物中分离得到了8个已知化合物,其结构经波谱解析分别确定为:(-)-kaur-16-en-19-oic acid(1)、(6R,10R)-6,10,14-三甲基-十五烷-2-酮(2)、维生素E(3)、dehydrocos-tus lactone(4)、(-)-α-tocospirone(5)、angeloygrandifloric acid(6)、trans-phytol(7)及3(20)-phytene-1、2-diol(8)。其中化合物2,5和8为首次从该植物中分离得到。     

向日葵花盘功能成分及研究现状

向日葵(Helianthus annuus L.)作为我国重要的油料作物之一,其葵花籽油的提取已经实现工业化生产,但其副产物向日葵盘、秸秆、葵花籽壳和饼粕等仍然利用不足.随着技术设备条件的优化及产业化条件的成熟,向日葵副产物具有十分广阔的开发应用前景.本文对向日葵花盘现阶段的综合利用情况进行介绍,并总结了向日葵花盘中绿原酸、水溶性多糖、萜类化合物等重要活性物质的提取方法.针对我国目前面临的向日葵作物综合利用发展中出现的向日葵花盘副产物处理难问题,阐述了向日葵花盘的药用价值及其重新开发和综合利用的方法,为向日葵花盘的利用提供指导.     

不同列当抗性的向日葵品种根系分泌物对向日葵列当种子萌发的影响

以对向日葵列当抗性不同的向日葵幼苗为材料,利用水培法收集其根系分泌物,经二氯甲烷萃取后结合硅胶柱色谱分离法,研究不同列当抗性的向日葵品种根系分泌物对向日葵列当种子萌发的影响。结果表明:(1)在一定浓度范围内,向日葵根系分泌物对向日葵列当种子萌发具有低浓度促进、高浓度抑制的作用;二氯甲烷萃取的向日葵根系分泌物浓度为0.1mg/mL时,其向日葵列当萌发率高于其他浓度的作用。(2)‘星火大白边’和‘白葵杂9号’根系分泌物提取物作用下向日葵列当萌发率最高分别为46.92%和43.88%,显著高于免疫品种‘MGS’根系分泌物提取物作用下列当的萌发率(27.81%)。(3)根系分泌物提取物正己烷-乙酸乙酯1∶1洗脱组分的萌发刺激活性显著高于其他组分,‘星火大白边’、‘白葵杂9号’和‘MGS’的该组分作用下向日葵列当最高萌发率分别为49.90%、45.66%和30.00%。(4)‘MGS’的根系分泌物提取物与GR24或脱氢木香内酯共同作用时种子萌发率显著低于GR24或脱氢木香内酯的单独作用,说明‘MGS’根系分泌物中可能含有抑制GR24或脱氢木香内酯刺激向日葵列当种子萌发的物质,使其对向日葵列当表现出免疫特性。     

Pericarp strength of sunflower and its value for plant defense against the sunflower moth,Homoeosoma electellum

Sunflower pericarps provide a barrier against seed feeding by larvae of the sunflower moth, Homoeosoma electellum. Pericarp hardening is thought to be accelerated by a phytomelanin layer beneath the hypodermis, but among germplasm with phytomelanin, broad variation in sunflower pericarp strength exists. To facilitate the use of pericarp strength in sunflower breeding, resistance to mechanical puncture was assessed for diverse sunflower germplasm, and feeding tests were used to evaluate whether differences in pericarp strength prevent H. electellum larvae from penetrating achenes. Test on field-grown sunflowers indicates that public restorer lines have lower pericarp strengths compared with maintainer lines and commercial hybrids at 14 days after the start of anthesis. Interspecific crosses or plant introduction (PI) accessions believed to be resistant to H. electellum, including PI 170415, comprised a group with exceptionally high pericarp strength relative to other germplasm. In subsequent tests on greenhouse-grown sunflowers, overall results were similar, but using field-grown plants provided greater statistical power. In choice tests with achenes that differed in pericarp strength, 7- to 9-day-old sunflower moth larvae fed more often on seed protected by a weaker pericarp, at a more than 5-to-1 ratio, while 10-day-old larvae fed indiscriminately. Pericarp strength data contradict previous published results for individual entries and heterotic groups, but support the generalization that improved physical resistance to the sunflower moth is possible. To use pericarp strength in PI 170415 or similar sources, the inheritance of high pericarp strength and potential trade-offs between pericarp strength and other agronomic traits need to be understood.     

Crop domestication disrupts a native tritrophic interaction associated with the sunflower, Helianthus annuus (Asterales: Asteraceae)

Abstract.  1. Crop domestication has been a largely overlooked factor that may explain why insect herbivores tend to be more abundant and less attacked in agricultural habitats than in native habitats. This study explores how domestication of the sunflower, Helianthus annuus L., affects the sunflower moth, Homoeosoma electellum (Lepidoptera: Pyralidae), and its parasitoids.
2. Common garden experiments were used to assess the effect of domestication on larval abundance in an agricultural and a native habitat. The effect of domestication on parasitism was determined using two studies: one study that manipulated nitrogen according to levels found in agricultural and native habitats, and a second common garden study in the native habitat.
3. At peak infestation in the agricultural common garden, larval abundance was 10 times higher on agricultural plants than on wild plants. In contrast, larval abundance did not differ between plant genotypes in the native habitat.
4. Larvae were four times more likely to be parasitised on wild sunflowers than on agricultural sunflowers, and three times more likely to be parasitised on low nitrogen plants than on high nitrogen plants. Parasitism did not differ between agricultural and wild plants in the native habitat, where flowers were more similar in size.
5. Sunflower domestication has increased larval abundance, accelerated larval development, and lowered parasitism. The magnitude of the effect appears to depend upon nutrient availability. Thus, domestication can disrupt tritrophic interactions, and may help explain why some insect pests are more abundant and less attacked in agro-ecosystems.     

Seasonal adaptations of different geographical populations of the sunflower moth, Homoeosoma electellum

A photothermogram constructed for a central Missouri population (ca. 39°N latitude) of the sunflower moth, Homoeosoma electellum (Hulst) predicted that this population has a seasonal life cycle of 2 complete and a partial third generation per year, and that daylengths of less than 13 h 30 min light/day and mean temperatures of less than 20°C induce the mature larval diapause. A test of the predicted life cycle revealed that larvae entered diapause when they were exposed from their first instar onwards to natural conditions in central Missouri beginning September 15, 1982. Sunflower moths obtained from northwest Texas (ca. 35°N latitude) and northeast South Dakota (ca. 45°N latitude) displayed shorter critical photoperiods for diapause induction at 20°C (12 h 30 min light/day and 12 h 15 min light/day, respectively) than did those from Missouri. The population of the sunflower moth obtained from South Dakota does not, therefore, appear to be adapted to local conditions, and moths might disperse from lower latitudes to establish transiet populations each year.     

Female preference and larval performance of sunflower moth,Homoeosoma electellum,on sunflower pre‐breeding lines

The preference–performance hypothesis for insect herbivores predicts that adult females should preferentially choose hosts on which their offspring perform better. We tested this hypothesis for the sunflower moth, Homoeosoma electellum (Hulst) (Lepidoptera: Pyralidae), using 16 sunflower (pre‐breeding) lines, derived from a number of wild species of Helianthus, including Helianthus annuus L., Helianthus deserticola Heiser, Helianthus paradoxus Heiser, Helianthus praecox Engelm. & Gray ssp. hirtus (Heiser) Heiser, Helianthus praecox Engelm. & Gray ssp. runyonii (Heiser) Heiser, Helianthus petiolaris Nutt., Helianthus resinosus Small, and Helianthus tuberosus L. (Asteraceae), that are suitable for introducing wild sunflower germplasm into commercial cultivars. Female moths showed a range of ovipositional preference measures to the various lines. Combined data for three Helianthus species represented by multiple lines showed significant differences in female preference with respect to the parental species. Larval performance, determined by proportion of infested neonate larvae reaching the pupal stage, or mean pupal weight, varied across the lines and, as for the female preference data, also showed significant differences among the three parental Helianthus species represented by multiple lines. These data suggest that the characteristics in the pre‐breeding lines influencing female sunflower moth preference and larval performance likely originate from the parental species and may be consistently transferred to the derived pre‐breeding lines. Of particular note with regard to potential plant resistance mechanisms, lines derived from H. tuberosus showed consistent low preference–performance measures. Female preference and larval performance (for both measures) were strongly correlated, indicating that females preferred plants and lines on which larvae performed better, in support of the preference–performance hypothesis.     

Host plant pollen influences calling behavior and ovarian development of the sunflower moth,Homoeosoma electellum

Summary Females of the sunflower moth, Homoeosoma electellum held in the presence of pollen, or an ethanolic pollen extract, from the sunflower Helianthus annuus initiated calling behavior at a significantly younger age following emergence than those provided sucrose only. Furthermore, females with pollen subsequently spent more time calling, and had an increased rate of egg maturation, than those held without pollen. These effects were attributed to a kairomone as females held in the presence of, but denied direct access to, pollen behaved in the same manner as those in contact with pollen. The importance of this life history strategy for the exploitation of temporarily available resources, essential to the survival of neonate larvae, and on the dispersal of adults, is discussed.     

Resistance in sunflower and interaction with Bacillus thuringiensis for control of banded sunflower moth (Lepidoptera: Tortricidae)

Four sunflower accessions were compared with a susceptible check, hybrid '894', in the greenhouse to determine their resistance to the banded sunflower moth, Cochylis hospes Walsingham, and their interaction with Bacillus thuringiensis Berliner variety kurstaki. Antibiosis, expressed as lower larval weight, was detected in all of the accessions. In addition to being antibiotic, sunflower accession Ames 3291 was antixenotic to banded sunflower moth oviposition and exhibited an additional impact on larval weight when B. thuringiensis was applied. By itself, B. thuringiensis provided better control of banded sunflower moth than the resistance tested. However, banded sunflower moth-resistant sunflower would be a good option when B. thuringiensis or another insecticide is not applied, and it may prevent the economic threshold from being reached.     

Using banded sunflower moth (Lepidoptera: Tortricidae) egg density to estimate damage and economic distance in oilseed sunflower

The banded sunflower moth, Cochylis hospes Walsingham (Lepidoptera: Tortricidae), is an important economic pest of sunflower in the Upper Great Plains of North America. Economic losses due to reductions in seed number, weight, and quality can be significant. Previously, the potential for economic losses were estimated by sampling for adult moths. However, sampling for moths can be difficult and inaccurate. An alternative is to sample for banded sunflower moth eggs, which can be accurately counted in the field by using a binocular 3.5 headband magnifier. The egg counts are used to calculate the economic injury level (EIL) (EIL = C/VWPK), where C is the cost of treatment per unit area, V is the crop market value per unit of weight, W is the slope of the regression between banded sunflower moth egg densities and weight loss per plant, P is a term for plant population per unit area, and K is the control treatment efficacy. Estimates of populations of banded sunflower moth eggs are taken from the center of 400-m spans along all field sides. From these samples and the calculated EIL, a map of the extent of the economically damaging banded sunflower moth population throughout the field is made using economic distance; ED = e ( ( (EIL/E)-1.458)/-0.262). Economic distance estimates the distance an economic population extends into the field interior along a transect from the sampling site. By using egg samples to calculate the EIL and mapping the distribution of economic populations throughout a field, producers can then make more effective pest management decisions.