牧草盲蝽的寄主种类及取食选择性研究

牧草盲蝽是多食性害虫,寄主种类广泛。研究牧草盲蜡的寄主种类及取食选择性,对于明确其发生地、虫源、预测预报及综合治理具有重要意义。采用目测法、盆拍法和扫网法,对牧草盲蝽的寄主植物种类和取食选择性进行了田间调查。通过本项研究查明新疆阿拉尔市牧草盲蝽的寄主植物为26科88种,其中偏好寄主有12科22种,非偏好寄主有23科66种;包括栽培植物64种,野生植物24种。     

河南省棉盲蝽发生原因及防治对策

河南省常见的棉盲蝽有绿盲蝽、中黑盲蝽、苜蓿盲蝽、三点盲蝽4种,其中绿盲蝽为优势种群。在河南省,棉盲蝽一年发生3～5代,其中棉田发生2～4代,以成虫和若虫通过刺吸式口器吸取汁液,为害棉花的嫩头、生长点、幼嫩花蕾及棉铃,造成破头、破叶、丛生枝、蕾铃大量脱落等。象,     

绿盲蝽对13种不同寄主植物适合度的初步研究

室内条件下研究了绿盲蝽在13种寄主植物上不同龄期若虫的发育历期和成虫的寿命。结果表明,绿盲蝽在不同寄主植物上不同龄期若虫的发育历期及若虫期均有显著差异,其中四季豆上若虫的发育历期明显缩短,其它寄主植物之间无明显差异;在常规棉花上若虫的发育历期延长,但和豆类及转基因抗虫棉相比无明显差异。在两种抗虫棉上成虫的寿命明显缩短,其它寄主植物之间无明显差异。说明转基因抗虫棉和豆类植物更适合绿盲蝽的生长发育。     

不同诱集植物对盲蝽的诱集效果比较

为了探索棉田盲蝽的农业防治技术,研究了9种诱集植物棉花(中棉所49、LB2、BJ2和HH2)、油葵、大豆、黄秋葵、凤仙花、玉米、苘麻、豇豆和黄瓜对棉田盲蝽的诱集效果。结果表明:不同的诱集植物诱集效果不同,且差异较大。其中苘麻的诱集效果最好,其次是凤仙花,平均百株盲蝽可达421.9头和27.2头,其他诱集植物上数量均低于10头,诱集效果差。诱集植物对盲蝽的诱集效果与其花期长短、开花集中程度以及花量等都有密切的关系。     

棉盲蝽的发生与防治

棉盲蝽又叫棉花盲蝽象,俗称"小臭虫",属半翅目盲蝽科,其种类很多,我国棉区已发现17种,山东记载有11种,主要的有绿盲蝽、苜蓿盲蝽、三点盲蝽和中黑盲蝽等4种.     

棉田绿盲蝽诱集植物的筛选和作用效果比较

通过对绿盲蝽的几种主要寄主植物的田间效果比较,筛选出了对绿盲蝽有显著诱集效果的2种植物——油葵和绿豆,其中,油葵优于绿豆,并提出了诱集植物的适宜播期和利用方式。     

茶网蝽的“克星”——军配盲蝽

军配盲蝽是茶网蝽的主要天敌,对茶网蝽的发生有较为明显的控制作用。文章介绍了该天敌的分布与发生情况、形态特征、生活习性、捕食能力和田间保护,以期为该天敌的识别和利用提供参考。     

赣北5种棉盲蝽取食习性及危害症状比较

 为提高认识和便于田间调查识别区分不同种类棉盲蝽的发生及危害症状,对江西赣北棉区中黑盲蝽、杂毛合垫盲蝽、绿盲蝽、赣棉淡盲蝽、小斜唇盲蝽5种棉盲蝽进行了棉花上取食习性和危害症状的观察、比较。     

河南省棉盲蝽的为害损失及控制目标研究

采用棉田系统调查结合罩笼的方法,研究了河南棉区棉盲蝽的为害特点,结果表明,棉花现蕾前后破坏主茎生长点,造成产量损失最为明显。分析了棉花不同生育期主茎生长点及花蕾被害后,棉花群体的补偿效应及实际产量损失,拟定了现阶段对棉盲蝽和棉花受害程度的防治指标,认为棉花第三果枝出现前的虫量和主茎生长点受害率分别为百株4头和3％,第四果枝出现后为百株6头和4％。按照这一防治指标棉花叶片和蕾的受害程度亦在允许水平之内。     

中华稻蝗对植物挥发性化学物质的触角电生理和行为反应

采用触角电位仪(EAG)和Y型嗅觉仪测定了中华稻蝗6龄若虫和成虫对9种植物挥发性化学物质的嗅觉和行为反应.EAG反应结果表明,中华稻蝗成虫对9种植物挥发性化学物质的反应值均低于6龄若虫,其中对顺-3-己烯-1-醇的EAG反应值6龄若虫显著高于成虫,对香叶醇的EAG反应6龄雌性若虫显著高于成虫及雄性若虫.1-戊醇可引发中华稻蝗雌、雄6龄若虫间显著的EAG反应差异,雌、雄成虫对9种挥发性化合物的EAG反应表现一致.行为测定结果表明,除6龄雄虫外,中华稻蝗其他各虫态对反-2-己烯醛和乙酸顺-3-己烯酯2种化合物均表现出显著的行为趋性.中华稻蝗对香叶醇的EAG反应和行为反应相一致.对水稻、稗草和马唐3种寄主植物的行为反应测定结果表明,中华稻蝗雌性成虫和雌性6龄若虫对马唐存在显著的行为趋向性,而所有试虫对水稻和稗草却表现出随机选择效应.因此,香叶醇很有可能会在中华稻蝗对寄主植物的定向行为中发挥重要作用,而对寄主植物的选择性可能会影响中华稻蝗雌虫的生长发育及产卵行为.     

A Molecular Approach for Detecting Stage-Specific Predation on Lygus hesperus (Hemiptera: Miridae)

A molecular gut analysis technique is described to identify predators of Lygus hesperus (Knight), a significant pest of many crops. The technique is unique because it can pinpoint which life stage of the pest was consumed. Sentinel egg masses designed to mimic the endophytic egg-laying behavior of L. hesperus were marked with rabbit serum, while third instar and adult L. hesperus were marked with chicken and rat sera, respectively. Then, the variously labeled L. hesperus life stages were introduced into field cages that enclosed the native arthropod population inhabiting an individual cotton plant. After a 6-h exposure period, the predator assemblage, including the introduced and native L. hesperus population, in each cage were counted and had their gut contents examined for the presence of the variously marked L. hesperus life stages by a suite of serum-specific enzyme-linked immunosorbent assays (ELISA). The whole-plant sampling scheme revealed that Geocoris punticpes (Say) and Geocoris pallens Stal (Hemiptera: Geocoridae) and members of the spider complex were the numerically dominant predator taxa in the cotton field. The gut content analyses also showed that these two taxa appeared to be the most prolific predators of the L. hesperus nymph stage. Other key findings include that Collops vittatus (Say) (Coleoptera: Melyridae) and Solenopsis xyloni McCook (Hymenoptera: Formicidae) appear to be adept at finding and feeding on the cryptic L. hesperus egg stage, and that L. hesperus, albeit at low frequencies, engaged in cannibalism. The methods described here could be adapted for studying life stage-specific feeding preferences for a wide variety of arthropod taxa.     

Overwintering hosts of Apolygus lucorum (Hemiptera: Miridae) in northern China

During the past decade, Apolygus lucorum Meyer-Dür (Heteroptera: Miridae) has become a key pest of cotton in northern China, due to widespread planting of Bt cotton and an associated drop in the use of broad-spectrum insecticides. Because of a lack of management alternatives, A. lucorum outbreaks are presently exclusively controlled with insecticides. In this study, we determined A. lucorum overwintering locations and host plants during the 2006–2009 winter seasons. A total of 126 plant species were screened and nymphal emergence of A. lucorum was monitored over time. Eggs of A. lucorum successfully overwintered in cotton field soils and on 86 plant species, including weeds, fruit trees, pastures and agricultural crops. More specifically, Vitis vinifera L., Ricinus communis L., Momordica charantia L., Artemisia argyi Levl. et Vant., Artemisia annua L., Artemisia lavandulaefolia DC., Isatis indigotica Fort., Artemisia scoparia Waldst. et Kit., Vigna radiate (L.) Wilczek, Ziziphus jujuba Mill., Vigna angularis (Willd.) Ohwi et, Ocimum basilicum L., Onobrychi viciifolia Scop., Pyrus bretschneideri Rehd., Malus domestica Borkh. and Brassica juncea (L.) Czern. et Coss proved optimal overwintering hosts of A. lucorum. Based upon plant species occurrence and distribution in Chinese cotton-growing regions, several weeds and fruit trees, such as V. vinifera, Z. jujuba, P. bretschneideri and M. domestica can be termed key overwintering hosts of A. lucorum. Our findings can form the basis for future formulation of targeted management actions to lower A. lucorum overwintering populations in cotton-growing landscapes of northern China.     

Infectivity of Entomopathogenic Fungal Isolates Against Tarnished Plant Bug Lygus lineolaris (Hemiptera: Miridae)

Twelve isolates of entomopathogenic fungi belonging to Metarhizium robertsii, M. pinghaense, M. brunneum, Beauveria bassiana, and Isaria fumosorosea were screened against tarnished plant bug. All isolates were pathogenic, causing mortality from 28.8 ± 3.4 to 96.3 ± 2.7%. The LT₅₀ values ranged from 2.7 to 6.0 d while the LT₉₀ values varied between 6.6 and 15.0 d. Metarhizium robertsii isolate CPD6 (will be under the trade name NoVil) was among the isolates that caused high mortality within shorter times and was selected for study on developmental stages and greenhouse trial. The third-, fourth-, and fifth-instar nymphs, and adults were inoculated with 10⁶, 10⁷, and 10⁸ conidia per ml of NoVil. All the stages were susceptible to fungal infection. However, third and fourth instars were the most susceptible with no significant differences in mortality across the three concentrations. On the other hand, mortality was dose-dependent with fifth-instar nymph and adult stages. The LT₅₀ and LT₉₀ values were also dose-dependent, with higher concentrations having shorter lethal-time values as compared to the lower concentrations. In the greenhouse, pepper plants were sprayed with NoVil and chemical insecticide Flonicamid (as industrial standard), before releasing adult tarnished plant bug. Mortality of 37.3, 75.5, and 76.3% was recorded in the control, NoVil, and Flonicamid, respectively. This study has identified NoVil as a potential mycoinsecticide candidate for the control of tarnished plant bug under greenhouse conditions. Further field testing on juvenile and adults is needed to evaluate the potential for in-field control.     

Chemical control of sorghum head bugs (Hemiptera: Miridae)

Eight contact and three systemic insecticides, and an enriched neem extract were tested for the control of sorghum head bug, Calocoris angustatus Leth. at the ICRISAT Center. The insecticides were applied at the complete-anthesis and milk stages (at 500 1/ha) with a knapsack sprayer. On the basis of effectiveness of head bug control, grain yield and 1000-grain mass, carbaryl (at 500 g a.i./ha) was the most effective insecticide followed by fenvalerate (at 50 g a.i./ha), and chlorpyrifos (at 250 g a.i./ha). Among the systemic insecticides, demeton-S-methyl (at 250g a.i./ha), was the most effective. Demeton-S-methyl and dimethoate were also effective for the control of other head bug species—Eurystylus bellevoyei Put. and Reut. and Campylomma sp. Plots sprayed with demeton-S-methyl gave higher grain yields than those treated with carbaryl, which was the best contact insecticide. Two sprays of carbaryl (at 500g a.i./ha) applied at the complete-anthesis and milk stages have been found to be effective for head bug control. Dichlorvos, fenitrothion and monocrotophos were highly phytotoxic and resulted in burning and drying of entire leaves. Dimethoate resulted in a slight drying of leaf tips and margins.     

Comparative overwintering host range of three Adelphocoris species (Hemiptera: Miridae) in northern China

In northern China, Adelphocoris suturalis, Adelphocoris lineolatus and Adelphocoris fasciaticollis (Hemiptera: Miridae) are common pests of cotton and several other crops. These species have vastly diverse geographic distribution, seasonal dynamics and abundance, the underlying causal factors of which are poorly understood. In this study, the importance of a broad range of plant species as overwintering hosts for each Adelphocoris sp. was compared. Nymphal emergence from a total of 126 plant species was monitored at two distinct locations. The eggs of A. suturalis successfully eclosed from un-plowed cotton field soil and 115 plant species, primarily pastures, weeds and agricultural crops. The eggs of A. lineolatus successfully eclosed from 40 plant species, mainly pastures and weeds. Finally, A. fasciaticollis overwintered on 35 plant species, primarily tree species, weeds and agricultural crops. In conclusion, the most common and widely distributed mirid species, A. suturalis, overwintered on a comparatively broader range of plants compared to the other two species. These observations help to understand the differences in geographical distribution and abundance of the three Adelphocoris species, and constitute the basis for forecasting and pest management protocols for Adelphocoris spp. in China.     

Relative Abundance of Carsonella ruddii (Gamma Proteobacterium) in Females and Males of Cacopsylla pyricola (Hemiptera: Psyllidae) and Bactericera cockerelli (Hemiptera: Triozidae)

Carsonella ruddii (Gamma Proteobacterium) is an obligate bacterial endosymbiont of psyllids that produces essential amino acids that are lacking in the insect’s diet. Accurate estimations of Carsonella populations are important to studies of Carsonella-psyllid interactions and to developing ways to target Carsonella for control of psyllid pests including pear psylla, Cacopsylla pyricola (Förster) (Hemiptera: Psyllidae) and potato psyllid, Bactericera cockerelli (Šulc) (Hemiptera: Triozidae). We used two methods, namely fluorescence in situ hybridization and quantitative polymerase chain reaction (qPCR), to estimate relative abundance of Carsonella in bacteriocytes and whole bodies of psyllids, respectively. Using these two methods, we compared Carsonella populations between female and male insects. Estimations using fluorescence in situ hybridization indicated that Carsonella was more abundant in bacteriocytes of female C. pyricola than in those of males, but Carsonella abundance in bacteriocytes did not differ between sexes of B. cockerelli. Analyses by qPCR using whole-body specimens indicated Carsonella was more abundant in females than in males of both psyllids. Neither fluorescence in situ hybridization nor qPCR indicated that Carsonella populations differed in abundance among adults of different ages (0–3 wk after adult eclosion). Using fluorescence in situ hybridization, Carsonella was observed in ovarioles of newly emerged females and formed an aggregation in the posterior end of mature oocytes. Results of our study indicate that female psyllids harbor greater populations of Carsonella than do males and that sex should be controlled for in studies which require estimations of Carsonella populations.     

起始供食时间对稻水象甲冬后成虫繁殖、取食和存活的影响

室内研究了稻水象甲冬后虫在春季获得寄主水稻前所经历的时间长短对其产卵、取食和存活的影响。供试虫（4月下旬采集）先用禾本科草坪草高羊茅饲养0、10、20、30和45 d（即供食水稻前时间）,然后用20~35 d龄的稻苗饲养,观察产卵等情况。结果表明,水稻供食前时间达到10 d后即可致使冬后虫产卵历期明显缩短,卵量下降,取食斑的数量和长度减少。当水稻供食前时间延长至20 d后,成虫在水稻上的存活历期开始明显下降。处理时间越长,对其后成虫在水稻上的生殖、取食和存活的影响越大。还讨论了春季早稻栽种时间对该虫一代发生的影响。     

松突圆蚧花角蚜小蜂雌性生殖系统、寄生习性及幼期发育的研究

松突圆蚧花角蚜小蜂（Coccobius azumai Tachikawa）是松突圆蚧（Hemiberlesia pitysophila Takagi）的主要寄生性天敌之一。解剖花角蚜小蜂的雌性生殖系统,发现其卵巢左右成对,每侧卵巢各由3条卵巢管组成;两侧卵巢管端丝集结在一起形成悬带,左右两侧悬带分离,不形成中悬带。通过电镜扫描观察,发现花角蚜小蜂产卵器上具毛形感觉器、感觉孔、表皮刺和腔形感觉器。花角蚜小蜂的寄生过程分为：搜索、寄主定位、寄主试探、穿刺、产卵和梳理等几个步骤。生殖方式为两性生殖和孤雌生殖,重寄生产雄性个体。个体发育经过卵、幼虫、蛹和成虫等4个虫态。