Transmission of barley yellow dwarf virus by cereal aphids collected from different habitats on cereal farms

Cereal aphids were collected from cereal crops, from Poa annua within cereal fields, from Lolium perenne pastures and from wild grasses in hedge bottoms and around farm buildings. The frequency of barley yellow dwarf virus (BYDV) transmission was assessed by aphid transmission tests. There were differences in transmission rates between aphid species, between host species and between years. The transmission rates of Rhopalosiphum padi from the different host species were broadly similar whereas for Sitobion avenae, P. annua within cereal fields was significantly better than the other host species. Wild grasses other than P. annua were relatively poor sources of virus. A large percentage of aphids frequently transmitted more than one strain, suggesting that host plants are often infected with more than one BYDV strain.     

cis-Jasmone treatment induces resistance in wheat plants against the grain aphid,Sitobion avenae (Fabricius) (Homoptera: Aphididae)

cis-Jasmone is a plant volatile known to have roles as an insect semiochemical and in inducing plant defence. It was evaluated in laboratory and field trials for control of cereal aphids. In an olfactometer bioassay cis-jasmone was repellent to alatae of the grain aphid, Sitobion avenae (Fabricius) (Homoptera: Aphididae). Moreover, wheat, Triticum aestivum (L), seedlings sprayed with formulated cis-jasmone 24 h previously were less susceptible to attack by S. avenae than control plants. In field simulator studies, significantly fewer alate S. avenae settled on cis-jasmone-treated plants over a 24-h period. In addition, the intrinsic rate of population increase, r(m), of S. avenae apterae was reduced on cis-jasmone treated seedlings. In a series of small-plot experiments conducted over four years, cis-jasmone applications reduced cereal aphid populations infesting wheat in the field.     

麦蚜与天敌相互关系研究及麦蚜防治指标初报

试验结果表明:小麦产量损失率与麦长管蚜、七星瓢虫幼虫关系极显著,与禾缢管蚜关系显著。经对田间麦蚜防治指标初步试验探讨,揭示了在麦蚜、天敌共存的农田系统内,由于天敌捕食控制作用,原来仅以麦蚜为害单因素所制定的防治指标可有较大幅度的放宽。     

七星瓢虫对两种麦蚜控制作用的模拟研究

应用二次回归旋转组合设计方法研究了七星瓢虫成虫、幼虫与两种麦蚜共存系统中瓢虫对麦长管蚜和禾谷缢管蚜的捕食量模型。结果表明七星瓢虫对两种麦蚜的捕食量随着瓢虫密度的增加而减少．随着该种麦蚜密度的增加而增加．且七星瓢虫无选择性。七星瓢虫不同个体间的干扰作用对其捕食麦长管蚜数量有显著影响,两种麦蚜数交互作用对七星瓢虫捕食禾谷缢管蚜数量影响显著。该模型可用来预测田间蚜虫的变化．指导麦田蚜虫防治。     

Biotypic and pest status differences between Hungarian and South African populations of Russian wheat aphid, Diuraphis noxia (Kurdjumov) (Homoptera: Aphididae)

Russian wheat aphid, Diuraphis noxia (Kurdjumov) is a severe pest of cereals in South Africa and in the USA. In order to reduce D noxia damage, intensive resistance breeding programs have been undertaken, resulting in D noxia-resistant cultivars that are now widely used in South Africa and in the USA. However, there appear to be differences in the ability of different populations of D noxia to damage these resistant cereal cultivars. To determine whether different biotypes of D noxia are present, damage to eight wheat cultivars was compared when they were exposed to either Hungarian or South African aphid strains. It appeared that the Hungarian CVS MV Magdaléna, MV Magvas, and MV 17 were susceptible to D noxia from both Hungary and South Africa. The susceptible South African CV Betta was also severely damaged regardless of the country of origin of the aphids. None of the cultivars resistant in South Africa (Caledon, SST 333, SST 972 and Halt) were, however, resistant to Hungarian populations of D noxia. These cultivars, which carry resistance genes originating from the breeding lines PI 262660, PI 137739 and PI 372129, were severely damaged by the Hungarian D noxia. Apart from the highly resistant CV Halt, the resistant cultivars used in this study were developed in South Africa, with the biotype present there. Damage to all cultivars tested was significantly more severe in response to Hungarian than to South African D noxia, indicating that a more damaging aphid biotype occurs in Hungary. However, D noxia has not yet become a pest of wheat in Hungary, possibly due to a difference in cultural practices.     

茉莉酸诱导小麦幼苗对麦蚜取食行为的影响

茉莉酸可诱导小麦品种郑州891的防御反应，使麦长管蚜Sitobion avenae(F.)和禾谷缢管蚜Rhopalosiphum padi(L.)的取食行为发生明显改变。尽管此两种蚜虫在正常的小麦相干株上取食的EPG各波型参数出现的次数及历时变化较大，但经茉莉酸诱导后，都再现了NP波次数和历时显著增加、E1与E2波历时明显缩短、首次出现E1波时间显著延长以及口针在细胞间穿刺频率明显升高等变化。这说明茉莉酸诱导后，郑州891的取食适合度降低，其机理与茉莉酸诱导产生挥发性的蚜虫取食拒避剂及诱导维管液营养成份的改变有关。试验还证实；麦长管蚜和禾谷缢管蚜的嗅觉和味觉感受器在其对寄主植物适合度的鉴别中共同起作用；植物适合度不能仅由1－2个EPG波形参数作为指示因子，要视具体情况全面分析，才能得出可靠的结论。     

小麦抗麦双尾蚜研究进展

麦双尾蚜是一种世界性的麦类害虫。本文就小麦抗麦双尾蚜资源筛选、抗性机制、抗性遗传、抗蚜基因染色体定位及分子标记研究进展进行了综述。     

河北廊坊小麦穗期蚜虫优势度和生态位分析

为明确华北小麦穗期主要蚜虫种类及其生态位, 为京津冀地区小麦蚜虫预测预报和科学防控提供技术支持，采用五点式和棋盘式取样法系统调查了河北廊坊小麦穗期不同蚜虫种类的种群动态及其在植株上的分布, 利用生态位理论, 计算荻草谷网蚜Sitobion miscanthi (Takahashi)、禾谷缢管蚜Rhopalosiphum padi (Linnaeus)和麦无网长管蚜Metopolophium dirhodum (Walker) 3种优势蚜虫的生态位宽度和重叠度。禾谷缢管蚜的时空生态位最宽, 其次为荻草谷网蚜和麦无网长管蚜, 其中禾谷缢管蚜的生态位宽度随时间推移呈上升趋势, 其他两种蚜虫呈下降趋势。不同蚜虫种类之间存在生态位重叠, 其中荻草谷网蚜与禾谷缢管蚜的重叠度最大, 为2.073 0, 荻草谷网蚜与麦无网长管蚜的重叠度最低, 为1.656 4; 随时间推移, 荻草谷网蚜与禾谷缢管蚜之间的竞争趋于增强, 禾谷缢管蚜与麦无网长管蚜之间的竞争趋于减弱, 而荻草谷网蚜与麦无网长管蚜的竞争关系相对稳定。荻草谷网蚜是当地小麦蚜虫主要优势种群, 禾谷缢管蚜时空生态位宽度最大, 与荻草谷网蚜竞争激烈, 麦无网长管蚜时空生态位相对稳定。     

Variation in Transmission Efficiency Among Barley yellow dwarf virus-RMV Isolates and Clones of the Normally Inefficient Aphid Vector, Rhopalosiphum padi

The RMV strain of Barley yellow dwarf virus (BYDV-RMV) is an unassigned member of the Luteoviridae that causes barley yellow dwarf in various cereal crops. The virus is most efficiently vectored by the aphid Rhopalosiphum maidis, but can also be vectored with varying efficiency by R. padi and Schizaphis graminum. Field collections of alate aphids migrating into the emerging winter wheat crop in the fall of 1994 in central New York identified a high proportion of R. padi transmitting BYDV-RMV. This prompted a comparison of the BYDV-RMV isolates and the R. padi populations found in the field with type virus and aphid species maintained in the laboratory. A majority of the field isolates of BYDV-RMV were similar to each other and to the type BYDV-RMV isolate in disease severity on oat and in transmission by the laboratory-maintained population of R. maidis and a field-collected population of R. maidis. However, several field populations of R. padi differed in their ability to transmit the various BYDV-RMV isolates. The transmission efficiency of the R. padi clones was increased if acquisition and inoculation feeding periods were allowed at higher temperatures. In addition, the transmission efficiency of BYDV-RMV was significantly influenced by the aphid that inoculated the virus source tissue. In general, BYDV-RMV transmission by R. padi was higher when R. padi was the aphid that inoculated the source tissue than when R. maidis was the inoculating aphid. The magnitude of the change varied among virus isolates and R. padi clones. These results indicate that, under certain environmental conditions, R. padi can play a significant role in the epidemiology of BYDV-RMV. This may be especially significant in regions where corn is a major source of virus and of aphids that can carry virus into a fall-planted wheat crop.     

宁夏麦蚜天敌多样性及种间关系

麦蚜是宁夏小麦的主要害虫,为了实现自然天敌对麦蚜的有效控制,采用网捕法和陷阱法等采集手段,通过3年田间调查,共鉴定麦蚜天敌97种,包括寄生性天敌16种和捕食性天敌81种。将麦蚜天敌划分为单食性天敌、寡食性天敌、多食性天敌及杂食性天敌共4类功能团进行分析,结果表明,不同天敌功能团对麦蚜种群的影响存在显著的交互作用;寄生性天敌中蚜茧蜂属的燕麦蚜茧蜂与烟蚜茧蜂是优势种;捕食性天敌种类较为复杂,不同地区麦蚜天敌组成存在显著性差异,复杂的农业景观能够维持更高的天敌多样性。表明在农业生态系统中建立和恢复非作物生境能够明显提高天敌种群数量,进而提高其生物防治作用。     

大麦黄矮病毒GPV与GAV株系间异源装配现象的初步研究

 以我国麦区的大麦黄矮病毒GPV、GAV株系为材料,利用它们的蚜传特异性,将由禾谷缢管蚜传播的GPV和由麦长管蚜传播的GAV混合侵染到岸黑燕麦上,并进行继代传毒。混合侵染后代蚜传表现型的变化初步表明存在异源装配现象,且表现型混合发生的比例较高。用DAS-ELISA和RT-PCR法对混合侵染后代进行了测定,进一步证明了异源包装现象的存在。部分基因的核苷酸序列分析初步显示所测定的混合侵染后代中没有发生基因重组。     

10个小麦品种（材料）对麦长管蚜的室内苗期抗蚜性*

［目的］ 明确不同小麦品种对麦长管蚜(Sitobion avenae)的室内苗期抗性。［方法］ 在温室内采用每株小麦接种1头蚜虫的方法,测定了麦长管蚜在来源于3个国家的10个小麦品种上的发育历期（DD）、相对日均体重增长量（MRGR）和成虫日均产仔数（Rm）,以此来确定不同小麦品种（材料）的抗蚜性。［结果］ 应用多元方差分析,多目标综合判别及聚类分析等方法分析表明,麦长管蚜在‘Ww2730’、‘98 10 30’、‘Astron’上的适应性最差,这几个品种对其抗性最好,是可以利用的抗性品种（材料）;‘98 10 35’、‘98 10 32’次之;‘Batis’对麦长管蚜的适应性最好,抗性最差;‘186Tm’,‘Xanthus’,‘Amigo’对麦长管蚜适应性较好,与作为对照的‘小偃 22’一样,抗性处在中间水平。［结论］ 研究结果可以为进一步的抗蚜育种提供依据。     

小麦抗虫品种对麦长管蚜种群及蚜茧蜂寄生和发育的影响

以不选择性为主的小麦抗蚜品种（系）KOK－1679、L1和小白冬麦可显著降低麦长管蚜的种群增长率，对燕麦蚜茧蜂的抗害作用没有负面影响。燕麦蚜茧蜂的控害作用可使小麦植株的株高增长率和叶面积显著提高，但使叶绿素含量提高幅度不大。以2龄麦长管蚜接蚜9日后，低感品种红芒红上该蚜的种群增长率为94．21％，而高抗品系KOK－1679仅为18．05％。对僵蚜及成蜂的观察表明，抗性品种（系）中的成蜂羽化时间缩短，羽化率升高，寿命延长。尽管其寄生率较红芒红低，但可能是麦长管蚜在不选择性抗蚜品种（系）上的定殖率低所致。     

Analyzing and Modeling Temporal Disease Progress of Barley yellow dwarf virus Serotypes in Barley Fields

ABSTRACT Population dynamics of Padi avenae (PAV), Macrosiphum avenae (MAV), and Rhopalosiphum padi (RPV) virus serotypes of Barley yellow dwarf virus (BYDV) and of their main aphid vectors were studied in winter barley (Hordeum vulgare) fields for three successive years in western France. An epidemiological model of the spread of viruses in the field was developed based on vector populations as forcing variables and the population dynamics of each virus serotype. This model accurately simulated the kinetics of the epidemic for PAV serotypes, which are the most common ones. For RPV and to some extent for MAV, the results were less satisfactory. The occurrence and spread of PAV and MAV serotypes in the field was clearly and easily related to that of their main vector species. Conversely, the spread of RPV serotypes showed no consistent relationships with the dynamics of their vectors. Incidence of PAV in 1989 to 1990 and 1990 to 1991 showed a bimodal distribution, with maximums in fall (December) and spring (May) that were linked to fall infestations by R. padi and spring infestations by three (R. padi, Sitobion avenae, and Metopolophium dirhodum) or two (S. avenae and M. dirhodum) aphid species. In 1991 to 1992, the PAV infection curve was monomodal and mainly due to a primary spread of the virus by very large populations of alate R. padi. MAV incidence was low in fall and winter and reached a maximum in spring 1990 and 1991 related to the occurrence of S. avenae and M. dirhodum. RPV incidence was low every year, despite the abundance of its vector, R. padi. Mixed infections were more frequent than expected by chance and were assumed to be partly related to heterologous encapsidation. The occurrence of each serotype is discussed in relation to the time of crop infection and possible damage.     

异色瓢虫显明变种对荻草谷网蚜和禾谷缢管蚜捕食选择性研究

在实验室条件下,在特定空间内,测定异色瓢虫显明变种对两种蚜虫荻草谷网蚜和禾谷缢管蚜不同密度值下的捕食量。结果表明,荻草谷网蚜和禾谷缢管蚜种群数量同步增加时,EG-S值和EI值变化是从1到∞,EI值是在0到+1范围内依次增加,表明异色瓢虫显明变种喜好捕食荻草谷网蚜明显高于禾谷缢管蚜;荻草谷网蚜数量不变,禾谷缢管蚜数量增加时,EG-S值和EI值是从+1到0,EI值从-1到0范围内依次减少,表明异色瓢虫显明变种明显喜好捕食禾谷缢管蚜;禾谷缢管蚜数量不变,荻草谷网蚜数量增加时,EG-S值和EI值变化从+1到∞,EI值在0到+1范围内依次增加,表明异色瓢虫显明变种明显喜好捕食荻草谷网蚜。捕食量结果同选择指数。     

小麦对麦长管蚜的耐害性及评估方法

为更有效地将耐害性用于小麦病虫害的绿色防控,该文就小麦对麦长管蚜的耐蚜性及其评估方法进行总结。具有耐蚜性的小麦受到一定数量蚜虫为害时,田间产量损失不明显,或能够通过生理生态途径补偿产量损失。耐蚜性不影响蚜虫的取食及生物学参数,对蚜虫进化压力小,因此田间表现更稳定。耐蚜小麦可以允许田间存在一定数量的蚜虫,这不仅可以减轻防治压力,还可以为天敌提供食物,有利于天敌的保护和利用,更符合有害生物绿色防控理念的核心。然而,目前抗麦长管蚜的小麦抗源鉴选主要是以蚜量为基础的抗生性和不选择性,耐害性被忽视。鉴于麦长管蚜田间蚜量与小麦产量(千粒重)损失率正相关,且峰值蚜量和小麦千粒重受损敏感期在小麦灌浆期重合,因此提出了以耐蚜值(千粒重损失率和灌浆期蚜情指标的比值)为依据计算耐蚜指数来评估小麦耐害性的方法,该方法可弥补抗源鉴选中忽视耐害性的不足,也能克服以田间千粒重损失率为依据评估耐害性时很难实现蚜量统一的不足,同时消除抗生性和不选择性带来的影响。     

Occurrence of barley yellow dwarf virus in cereals and grasses of the low-rainfall wheatbelt of South Australia

South Australia is in the dry temperate zone where most cereal crops are grown in an area of low rainfall, with a crop-free season from December to April. The incidence of barley yellow dwarf virus (BYDV) was assessed by ELISA from 1989 to 1991 in wheat crops and irrigated pastures of South Australia. The incidence of BYDV was low in most wheat crops of the low-rainfall area in 1989 and 1990 (less than 1% of plants infected), but moderate levels of infection (1–10%) were observed in some early-sown crops. BYDV infection was more widespread in the high-rainfall area (south east of South Australia). A high incidence of BYDV was observed in the irrigated pastures of the three areas surveyed (4–86%). Of the five previously described strains, the Rhopalosiphum padi/Sitobion avenae strain (PAV) was the most common in wheat samples (> 90%). PAV and the R. padi-specific strain (RPV) were found in pasture grasses, alone or in mixed infection. Virus incidence was greater in Festuca spp. (56%) and Lolium perenne (30%) than in other species (2-–9%).     

小麦叶片营养物质与抗麦长管蚜的相关性分析

为了阐明小麦叶片营养物质与小麦抗蚜性之间的关系,观察了麦长管蚜Sitobion avenae(F.)在不同小麦品种上的选择趋性,测定其相对日均体重增长率,并采用Branford法和高效液相色谱技术分别测定了不同品种小麦叶片总蛋白、韧皮部中游离氨基酸以及可溶性糖的含量。结果表明,麦长管蚜显著趋向于铭贤169、西农889与西农1376;在铭贤169、西农889和西农1376上的成蚜相对日均体重增长率显著大于中四-有芒、小偃22;西农889叶片的总蛋白含量最高,为2 822.04μg/mL,小偃22叶片韧皮部的可溶性糖含量最高,铭贤169和西农889叶片韧皮部的游离氨基酸总含量相对较高,分别为1 424.3、1 301.1 nmol·L~(-1)·g~(-1)DW;各游离氨基酸在相对抗蚜品种中四-有芒和小偃22中的绝对含量与其抗蚜性无相关性。研究表明,中四-有芒、小偃22对麦长管蚜具有较强的抗性,植物营养在小麦抗蚜性中起到一定作用。     

Effects of the saprophytic leaf mycoflora on growth and productivity of winter wheat

The effects of the saprophytic mycoflora and its interference with cereal aphids on growth and yield of winter and spring wheat was studied in field experiments in 1980, 1981 and 1982.Yields varied between 5000 and 8000 kg dry matter of kernels per ha. The effect of the saprophytic mycoflora on yield was determined in different treatments: A) no control measures against cereal aphids and saprophytic and necrotrophic fungi, B) no control of cereal aphids, control of saprophytic and necrotrophic fungi, C) control of cereal aphids and control of saprophytic and necrotrophic fungi, D) control of cereal aphids and stimulation of saprophytic mycoflora and E) control of cereal aphids, no control of saprophytic and necrotrophic fungi nor stimulation of saprophytic mycoflora.Considerable differences in top densities of saprophytic mycoflora (10 times as large in A and D as in B and C) were determined. The consequences of these differences for the growth and productivity of wheat were minor. A negative effect of saprophytic mycoflora on the yield could not be detected in 1981 and 1982, whereas a small positive significant effect was found in 1980. This stimulation may have been due to competition between necrotrophic fungal pathogens and saprophytic mycoflora. As a result of favourable weather conditions necrotrophic fungal pathogens were very numerous in 1980 and could form an important yield reducing factor. Yield levels may effect the importance of the necrotrophic and saprophytic mycoflora as yield reducing factors. Additionally, in the presence of aphid honeydew captafol was found to be relatively ineffective against saprophytic fungi.     

麦田蚜茧蜂的初步研究

武昌麦田蚜茧蜂共有5种,以燕麦蚜茧峰、烟蚜茧蜂为优势种;重寄生蜂有三种,以黄足分盾细蜂为优势种。蚜茧蜂4月中、下旬进入麦田,5月中旬种群数量达到高峰:蚜茧蜂种群数量主要受寄主—蚜虫密度和4～5月的雨量,相对湿度的影响。麦田蚜茧蜂对麦蚜有一定的控制作用,寄生率最高可达40％以上。解决好重寄生和跟随现象的问题,可提高好苗蜂对麦蚜的控制效果。