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1.
Spread of the aphid-transmitted cucumber mosaic virus (CMV) and potato virus Y (PVY) in pepper plots was markedly reduced by growing the plants under a white coarse-net cover permitting normal development of the plants. This net also reduced the winged aphid population on the plants by more than 40 times. Light grey and yellow nets also reduced virus spread and aphid populations, but were much less effective than white ones. The nets do not act as a mechanical barrier to aphids. It is suggested that under white and grey netting, aphid repellency and microclimatic conditions are the primary causes of virus check, while the controlling effect of the yellow nets may be explained by their being more attractive to aphids than the plants. A reduction of “background effect” and a limiting of the aphids’ vision range by nets are probably other factors involved in the protective mechanism.  相似文献   

2.
In the south-west of England, cereal aphids can spread barley yellow dwarf virus and reproduce during winter. Ground-living polyphagous predators may be important in controlling these active cereal aphids. This 2-year study investigated the effect of deltamethrin on predator numbers, using pitfall traps. A randomised block design was used in an area of winter wheat (cv. Aquilla) in which deltamethrin-treated and control plots were surrounded by polyethylene barriers. Pitfall catches of polyphagous predators were reduced by about 30% in the treated plots compared with the control plots.  相似文献   

3.
田间飞翔蚜虫传染大豆花叶病毒(SMV)的模型预测   总被引:1,自引:0,他引:1  
 本文提出一个飞翔蚜虫非持久性传染植物病毒的侵染概率模型。设置绿色诱盘捕捉着落大豆株冠的蚜虫估计飞翔翅蚜日平均着落株冠次数。采用诱饵植株测定田间一定传染性病株率和飞翔蚜量条件SMV的日侵染率,对迁飞着落蚜虫群体传染SMV的效率进行估计,实现模型对SMV日侵染率的预测。结合显症率预测,对两年三个区的SMV病株率发展动态用模型拟合回测,平均准确度为90.18%,对两年非建模的两区病株率发展动态拟合预测,平均准确度为88.41%。  相似文献   

4.
杭州地区油菜病毒病的发病规律及防治研究   总被引:1,自引:0,他引:1  
油菜苗期病毒病的发生,决定于带毒有翅蚜从毒源寄主上迁入的时间与虫口数;本田期病毒病的流行为害,在很大程度上与苗床后期和本田初期有翅若蚜的长成和扩散有关。杭州地区的传毒蚜虫主要为菜缢管岈,其有翅蚜的发生及迁飞高峯期约在9月下旬至10月下旬,油菜病毒病发病率的高峯与有翅蚜发生高峯成正相关。本研究进一步证实了带病的十字花科杂蔊菜的蓿根,越夏后萌发的植株是秋菜及油菜的重要毒源之一。在7月中旬正8月上旬的炎热夏天仅看到火白菜是菜缢管蚜的寄主,但未检查到病株,另一试验火白菜感病后无隐蔽现象。杭州地区10月份的降水量、降雨天数以及相对湿度对当年病毒病流行与否影响最大,天气干旱病毒病相当严重。暴雨或连续降雨两天以上能影响有翅蚜,发生量与迁飞量显著下降,因而在一定程度上抑制了病毒病的蔓延。播种时用6%可湿性六六六粉每亩3斤撒施畦面,苗床期两片真叶开始,连续用乐果及二二三、六六六混合液治蚜4次,与加强肥水管理,效果达84.7%。  相似文献   

5.
甘藍蚜、桃蚜和棉蚜的有翅型与无翅型,均能传播大白菜病毒病,其中以甘藍蚜为最主要的传毒介体。一头带毒蚜可使80%的健苗发病;一头无毒蚜經吸毒一分钟的传病率为35%;健苗經一头有毒蚜传毒一分钟,就有10%发病。病毒系非持久性的,蚜虫一次吸毒后的传毒期限为25分钟左右。在烏魯木齐地区,有翅甘藍蚜全年中的迁飞高峯期,都是在7月下旬。証实了这时期与大白菜病毒病的流行,有极密切的关系。当年春、夏季播种的甘蓝和苤藍,尤其是晚甘蓝和晚苤蓝,是大白菜(包括冬蘿卜)苗期的初次毒源和蚜源。初步認为,能感染病毒的几种十字花科及藜科杂草,不是本病病毒和甘藍蚜的重要越夏寄主。  相似文献   

6.
1985~1986年,在杭州东郊系统调查了13块地5种十字花科蔬菜上蚜虫的寄生性天敌和被寄生率。共发现原寄生蜂两种,即菜小脉蚜茧蜂和烟蚜茧蜂,前者寄生于桃蚜和萝卜蚜,后者仅寄生于桃蚜,寄生率大多在0~3%,很少超过10%,在蚜虫数量上升阶段寄生率一般呈下降趋势,只有在蚜虫数量迅速下降阶段才明显上升,故蚜虫数量变化受寄生蜂影响不大。共发现重寄生蜂5种,重寄生率平均约为50%,高时接近100%。表明重寄生蜂在一定程度上影响了蚜茧蜂对蚜虫的控制效能。  相似文献   

7.
Potato virus Y is the major cause of crop losses in pepper in KwaZulu-Natal Province, South Africa. An evaluation of the efficacy of five treatments to reduce transmission of the virus to pepper by aphids was conducted. The use of white plastic mulch was the most effective, resulting in a 32% yield increase over the untreated control. Yellow sticky plastic traps also had a significant beneficial effect on the yield, but mineral oil sprays as well as a neem-derived product were ineffective. Weekly mercaptothion (malathion) sprays caused an increase in virus incidence, and yields were only 49% that of the untreated control.  相似文献   

8.
The behavioural events associated with acquisition of tobacco etch potyvirus by starvedMyzus persicae during single, electrically-recorded penetrations of plants or a Parafilm membrane were compared. Twenty nine percent of aphids acquired virus from plants and subsequently transmitted to test plants. Stylet puncture of the plasmalemma, indicated by a potential drop (pd) to the intracellular signal voltage level, occurred during 84% of penetrations, and virus transmission was always associated with this behavioural event during acquisition. Periods of intracellular stylet tip location, known as pd phase II, ranged from 3.6–12.2s, and always comprised three consecutive sub-phases, designated II1, II2 and II3. Ninety six percent of pds included distinct pulses during phase II3. A waveform which closely resembled these pulses was produced by 59% of aphids that probed a virus suspension through a Parafilm membrane; nineteen percent of the aphids subsequently transmitted membrane-acquired virus and transmission was significantly associated with the occurrence of the phase II3-like pulses during acquisition. The duration of occurrence of recorded phase II3 pulses, either on plants or thein vitro system, did not influence the virus transmission efficiency of aphids. The association of virus uptake from aqueous suspension with a particular behavioural activity is discussed as evidence for the ingestion-egestion hypothesis for nonpersistent transmission. Starved aphids acquiring virus from infected leaf tissue or thein vitro system had significantly higher transmission efficiencies than non-starved aphids. Starved and non-starved insects were electrically-recorded penetrating the artificial membrane, and again there was a clear difference in transmission efficiency (starved aphids, 26%; non-starved aphids, 2%). The higher transmission efficiency of starved insects could not be explained by behavioural differences, and the results lend support to the hypothesis that non-behavioural factors determine the enhancement of potyvirus transmission by preacquisition starvation.Abbreviations BMV Beet mosaic virus - EMF Electromotive force - HAT Highly aphid-transmissible - HC Helper component - pd Potential drop - PVY Potato virus Y - TEV Tobacco etch virus  相似文献   

9.
Yield reductions ofca 50% or more were observed in field plots infected with both sweet potato feathery mottle virus (SPFMV) and sweet potato sunken vein virus (SPSVV) (‘complex’), compared with plots planted with virus-free propagation stocks. No yield reductions were observed in a plot planted with SPFMV-infected cuttings. In plots infected with SPSVV alone, no significant effect on tuber yields was observed in one year, whereas in the second year there was aca 30% reduction in yield compared with virus-free control plants. Reinfection in the field, in the absence of introduced infection sources, was observed only with SPSVV. However, natural spread resulted when SPFMV-infected source plants were introduced. This implies that aphid vectors were present during the growing season, but that SPFMV infection sources were absent from the area.  相似文献   

10.
卫青萝卜病毒病生态防治技术研究   总被引:2,自引:0,他引:2  
经生物学、血清学测定,引起天津市卫青萝卜病毒病的毒源主要为TuMV,占67%,菜缢管蚜偏嗜十字花科蔬菜,是传播TuMV的主要介体,其寿命,繁殖力和迁飞受环境因素影响。病毒病的生态防治技术重点是控制蚜虫为害,方法为:地周种植韭菜,玉米隔离带;设银灰塑料条屏障,避开蚜虫迁飞高峰,适期(8月12日)播种,蚜虫传播期喷洒50%病毒1号油乳剂250倍。  相似文献   

11.
Populations of two aphid species from different geographic regions of Morocco were tested for their ability to transmit five barley yellow dwarf virus-PAV (BYDV-PAV) type isolates using Clintland 64 oat as the test plant. Transmission efficiencies were determined for 10 sub-populations of Rhopalosiphum padi and 12 sub-populations of Sitobion avenae. After a short acquisition access period (AAP) of 4h, all populations transmitted the virus but with different efficiencies. R. padi (Rp-S) and S. avenae (Sa-S) collected in the Settat region were the most efficient vectors, with transmission rates of 38% and 27%, respectively. R. padi (Rp-C) collected at Chaouen and S. avenae (Sa-B) at Berkane, were poor transmitters with respective vectoring abilities of 20% and 16%. These four sub-populations were chosen to study the acquisition of BYDV-PAV and the retention of virus within aphids in more detail. The transmission after two AAPs of 4h and 48h were compared. Starved aphids given a 4h AAP had significantly higher transmission efficiencies than non-starved aphids. However, after a 48h AAP, no difference was observed in the transmission between starved and non-starved aphids. Intraspecific variability was also detected by means of serial transfers of individual aphids after the given AAP. Following the first day of serial transfers, no differences were observed in transmission efficiency and virus titers for sub-populations within each species acquiring the virus during 48h, but there was significant variation when the virus was acquired in 4h. The levels of PAV antigen retained by aphids fed on healthy plants declined rapidly during the first day after acquisition, but remained fairly constant during the next 5–7 days depending on the length of the AAP. Virus antigen could be detected by ELISA in Rp-S and Sa-S for up to 11 days of serial transfer, but it was shown that aphids could retain and transmit BYDV-PAV for at least 3 weeks.  相似文献   

12.
Soil solarization provided effective control of bacterial canker of tomato in plastic houses. Trials in plastic houses in Preveza County, Greece, during the period 1990–1992 showed that soil solarization (approximately 6 weeks of soil mulching with transparent polyethylene sheets) drastically reduced disease incidence throughout the cropping season. In contrast, soil fumigation with a recommended rate of methyl bromide (70 g/m2) was ineffective. Both wild-type and antibiotic-resistant strains of Clavibacter michiganensis subsp. michiganensis , growing on Nutrient Agar Glycerol (NAG) medium within covered and screwed vials and embedded at various soil depths (5, 15 or 25 cm) before soil solarization, were studied. Weekly sampling of bacteria during treatment showed a sharp decline of populations in the solarized soil compared to the non-treated control plots 4–6 weeks after soil tarping. Populations of marked strains infiltrated into tomato stem segments and buried in the soil decreased significantly after 5–6 weeks of solarization compared to non-treated control plots. The data presented here suggest that soil solarization is useful for the control of bacterial canker of tomato in plastic houses in Greece.  相似文献   

13.
荻草谷网蚜Sitobion miscanthi是严重威胁我国小麦生产安全的迁飞性害虫。蜕皮激素是参与蚜虫翅型分化调控的内激素, 在有翅成蚜体内保持高滴度, 且诱导后代产生更高比例的无翅蚜, 其进出靶细胞需要经过细胞膜上特定蛋白的转运。ATP结合盒转运蛋白家族G亚家族(ATP-binding cassette transporter G, ABCG)中的 ABCG1是通过跨膜转运昆虫类固醇、对蜕皮激素信号进行负调控的功能蛋白之一, 在蚜虫中尚未见报道。本文克隆了荻草谷网蚜ABCG1(SmisABCG1)基因, 并进行了序列比对、系统进化分析以及不同组织部位和发育时期表达模式分析。结果显示, SmisABCG1基因的开放阅读框全长为1 851 bp, 编码616个氨基酸, 含7个跨膜结构域, 符合ABCG蛋白家族典型结构特性, 基因登录ID:OP626323。昆虫间ABCG1较保守, 该蛋白系统进化关系与各自物种间亲缘关系的远近保持一致。其中, SmisABCG1与来自豌豆蚜、禾谷缢管蚜、棉蚜、花生蚜和雪松长足大蚜等的ABCG1氨基酸序列高度一致(>87%), 以上蚜虫聚为一支。与SmisABCG1亲缘关系最近的是豌豆蚜的ABCG1, 其次是半翅目的褐飞虱、白背飞虱和灰飞虱, 与膜翅目的新疆菜叶蜂、阿里山潜蝇茧蜂以及鞘翅目的赤拟谷盗、蜂箱小甲虫亲缘关系较远。该基因在伪胚胎和成蚜阶段高表达。包含伪胚胎的有翅、无翅成蚜整蚜SmisABCG1的转录水平无显著差异, 但其在来自有翅成蚜的伪胚胎中的转录水平高于无翅成蚜伪胚胎, 证实无翅成蚜自身的转录水平较高, 而有翅成蚜较低。进一步分析显示这一差异主要是无翅蚜胸部显著高表达所导致。基于该蛋白对蜕皮激素负调控, 与有翅成蚜转录水平低, 但蜕皮激素水平更高相符合。  相似文献   

14.
Insect-borne viruses promote several changes in plant phenotype, which can modify plant-vector interactions in favor of virus survival and dissemination. Although co-infections commonly occur in the field, little is known about their effects on interactions with the vector. The ecological interactions between Barley Yellow Dwarf Virus (BYDV) and its aphid vector, Rhopalosiphum padi, have been investigated extensively, but the vector’s behavior in more complex scenarios has yet to be examined. We assessed olfactory response and performance of R. padi to wheat singly and doubly infected by the pathogenic fungus Giberella zeae and BYDV. Non-viruliferous aphids preferred odors of BYDV-infected wheat over healthy wheat, as previously reported in the literature, and they were still preferentially attracted to BYDV-infected plant during co-infection. However, around 35% more non-viruliferous aphids chose healthy wheat over G. zeae-infected wheat. Viruliferous aphids did not show any preference to the treatments. BYDV-infected wheat was a superior host than healthy wheat for the aphids whose population increased in 25%. We observed a synergistic effect of the co-infected wheat, which was the best host for aphids, and promoted an elevation of 42% on population growth. Our results indicate that co-infection might be beneficial for virus spread as does not interfere with aphid olfactory preference and provides greater colony growth than in singly infected plants.  相似文献   

15.
利用食蚜瘿蚊防治保护地蔬菜桃蚜的试验   总被引:2,自引:0,他引:2  
在蔬菜温室、弓棚、大棚内释放食蚜瘿蚊防治桃蚜,当单株蚜量在200头以下时,以1:20益害比释放瘿蚊成虫,9~12天后温室、弓棚内桃蚜分别减退75.1%~91.8%和80.1%~90.5%。1990年在5个大棚内以1:20益害比,一次释放,10天后蚜虫减退82.2%,30天后蚜虫有所回升,单株蚜量141.2头。1991年6~7月份,在16个大棚内分别释放瘿蚊,当单株蚜虫146头时,按1:20益害比,在2周内分2~3次释放瘿蚊,10天后单株蚜量减退86.4%,以后蚜虫仍逐日下降,在拉秧前60天内能有效地控制蚜害,不需使用化学农药。  相似文献   

16.
A two-year study was conducted to determine the effect of six sanitation treatments on leaf litter density (LLD), relative ascospore production of Venturia inaequalis and scab incidence on spur-leaf clusters, leaves and harvested fruits, on two cultivars with low and high scab susceptibilities, in Hungarian integrated and organic apple orchards. The following sanitation treatments were used: sprays of lime sulphur in autumn, collecting fallen leaves in autumn, straw mulch cover in late winter, sprays of lime sulphur followed by mulch cover, collecting fallen leaves followed by mulch cover, collecting fallen leaves followed by covering the orchard floor with plastic foil, and non-sanitized control. LLD decreased continuously in all treatment plots by 0–23% by mid-May in both orchards and years; however, LLD reduction was 1.4–4.2 times higher in the organic orchard compared to the integrated one. All treatments, except for the lime sulphur treatment, resulted in significant (P < 0.05) reduction of LLD and ascospore production in both the integrated and organic apple orchards compared to non-sanitized plots. The most efficient treatment was leaf collection combined with plastic foil cover, followed by leaf collection combined with mulch cover, leaf collection alone, mulch cover alone, and lime sulphur spray combined with mulch cover, with a reduction in the ascospore production of >95, 72–92, 56–79, 24–38, and 27–46%, respectively, in the mean of both orchards and years. However, only treatments of leaf collection applied alone, or in combination with mulch or with plastic foil cover reduced significantly (P < 0.05) leaf and/or fruit scab incidence by 18–57% compared to non-sanitized plots. These three leaf collection treatments are recommended in both integrated and organic orchards and the possibilities of successfully incorporating these methods into orchard management practices are interpreted.  相似文献   

17.
Exposure of banana bunchy top virus (BBTV)-infected plantlets of Cavendish banana to 40°C for 16 h daily for periods of up to 5 weeks did not free them from BBTV. However, BBTV was less readily transmitted by aphids from treated plants than from untreated controls. The same heat treatment applied for up to 12 weeks also failed to eliminate the virus from BBTV-infected tissue. When similar BBTV-infected tissue was cultured for 3 months at 35°C some of the buds started to produce healthy looking plantlets. Five out of 11 cultures produced healthy-looking plantlets in 6 months. Crude extracts from the leaves of these plantlets did not react with a monoclonal antibody prepared against BBTV. When heat-treated, healthy-looking plantlets were inoculated with viruliferous aphids all plants developed bunchy top symptoms indicating that they were not resistant to BBTV. The results suggest that the uneven distribution and low concentration of virus after treatment at high temperature leads to BBTV-free primordial cells which in turn may develop into healthy plantlets.  相似文献   

18.
为了研究我国不同地区麦蚜携带大麦黄矮病毒麦二叉蚜麦长管蚜非专化性株系(BYDV GAV)比率的差异,采用RT-PCR技术,对BYDV-GAV的传毒介体麦蚜带毒情况进行检测.所用方法具有较高的灵敏度和特异性,测定样本用量可少至1/200头蚜虫;对采自我国主要麦区的蚜虫样本进行分子检测,山西、甘肃、青海、陕西11个小麦黄矮病重病区蚜虫样本带毒率为56%~91.5%,而河北、河南两省4个非重病区蚜虫样本带毒率为2.5%~33%.通过试验证实,我国不同地区麦蚜携带BYDV-GAV比率存在差异,小麦黄矮病重病区山西、甘肃、青海、陕西等地的麦蚜带毒率高,而非重病区河北、河南等地的麦蚜带毒率低.  相似文献   

19.
山核桃透翅蛾幼虫头部感器电镜扫描观察   总被引:1,自引:0,他引:1  
本研究结合体式显微镜和扫描电镜,对有翅型与无翅型麦长管蚜各龄期的外部形态进行详细测量和系统观察。结果表明:1)麦长管蚜1、2龄若蚜外部形态无明显差别,触角均为5节;2)3龄有翅若蚜中胸发达,可见初生翅芽,至成虫期发育为完整的翅;3龄无翅若蚜中胸结构简单,未见翅芽,3龄至成蚜触角均为6节;3)1龄若蚜尾片呈瘤状,着生2根刚毛;2、3、4龄若蚜尾片呈圆锥形;有翅成蚜尾片呈长锥形,无翅成蚜呈长舌状,2龄若蚜至成蚜尾片均着生6根以上刚毛。本文首次探讨了麦长管蚜有翅型与无翅型成、若蚜外部形态的差异,并分析了其与麦长管蚜的生活史、迁移特性等特征之间的关系,以期为麦长管蚜分化的相关机理研究提供参考。  相似文献   

20.
本研究结合体式显微镜和扫描电镜,对有翅型与无翅型麦长管蚜各龄期的外部形态进行详细测量和系统观察。结果表明:1)麦长管蚜1、2龄若蚜外部形态无明显差别,触角均为5节;2)3龄有翅若蚜中胸发达,可见初生翅芽,至成虫期发育为完整的翅;3龄无翅若蚜中胸结构简单,未见翅芽,3龄至成蚜触角均为6节;3)1龄若蚜尾片呈瘤状,着生2根刚毛;2、3、4龄若蚜尾片呈圆锥形;有翅成蚜尾片呈长锥形,无翅成蚜呈长舌状,2龄若蚜至成蚜尾片均着生6根以上刚毛。本文首次探讨了麦长管蚜有翅型与无翅型成、若蚜外部形态的差异,并分析了其与麦长管蚜的生活史、迁移特性等特征之间的关系,以期为麦长管蚜分化的相关机理研究提供参考。  相似文献   

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