模拟气候变暖对不同纬度带麦长管蚜和禾谷缢管蚜种群动态的影响

为明确气候变暖对不同纬度带麦田麦长管蚜Sitobion avenae和禾谷缢管蚜Rhopalosiphum padi种群动态的影响,在高纬度的河北省廊坊市(39°30′N,116°36′E)和相对低纬度的河南省原阳县(34°55′N,114°15′E)开展红外线辐射增温试验,调查廊坊市(+2.00℃)和原阳县(+1.18℃)2个试验点的增温处理小区和对照小区麦长管蚜和禾谷缢管蚜的种群动态,并计算其盛期发生比值。结果表明,增温使廊坊市试验点的麦长管蚜始见期、峰期分别提前21、7 d,使原阳县试验点的麦长管蚜始见期、峰期分别提前14、14 d;而禾谷缢管蚜的始见期和峰期仅在原阳县试验点提前31 d和7 d。增温使廊坊市试验点的麦长管蚜盛期蚜量、峰期蚜量分别显著增加了139.21%和77.83%,禾谷缢管蚜盛期蚜量和峰期蚜量分别显著增加了157.31%和130.16%;增温使原阳县试验点的麦长管蚜盛期蚜量、峰期蚜量分别显著增加了149.62%和176.52%,禾谷缢管蚜/麦长管蚜的盛期蚜量比值显著降低了43.21%。表明增温有利于高纬度地区(廊坊市)麦长管蚜和禾谷缢管蚜种群增长,而在低纬度地区(原阳县)仅有利于麦长管蚜种群增长。     

蚜虫及大麦黄矮病毒诱导小麦对后期禾谷缢管蚜酶活性的影响

为探究植物病毒-介体昆虫-寄主植物三者之间的互作关系,以前期经携带/未携带大麦黄矮病毒(BYDV)PAV菌株的禾谷缢管蚜危害的小麦为材料,研究后期取食的禾谷缢管蚜体内过氧化物酶(POD)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)等保护酶和酸性磷酸酶(ACP)、碱性磷酸酶(AKP)、乙酰胆碱酯酶(AchE)等解毒酶的活性变化。结果表明:与取食健康小麦(对照组)相比,取食前期经无毒禾谷缢管蚜危害后的小麦(蚜虫诱导组)后,禾谷缢管蚜体内POD、CAT、SOD、ACP、AKP活性均显著升高,分别升高206.9%、138.9%、161.7%、190.8%和138.9%,说明小麦受蚜虫危害后,对后期禾谷缢管蚜产生不利的影响,后期蚜虫通过升高保护酶和解毒酶活性来适应这种影响;与取食健康小麦(对照组)相比,取食前期经有毒禾谷缢管蚜危害后的小麦(病毒和蚜虫诱导组)后,禾谷缢管蚜体内SOD、AKP活性均显著降低,分别降低27.8%和34.3%。且与蚜虫诱导组相比,病毒和蚜虫诱导组禾谷缢管蚜体内POD、CAT、SOD、ACP、AKP活性均显著降低。说明大麦黄矮病毒存在条件下,不仅抵消前期蚜虫危害导致的酶活性上升,还降低部分保护酶和解毒酶的活性。     

主要次生物质对麦蚜的抗性阈值及交互作用

用麦蚜全纯人工饲料加不同浓度次生物质的薄膜饲养技术,研究了8种次生物质对麦长管蚜(Sitobion avenae)及禾谷缢管蚜(Rhopalosiphum padi)生长、发育及若蚜增重等生命参数的影响和4种次生物质对麦长管蚜的复合作用。结果表明,除芸香苷外其余几种次生物质具不同程度的抗蚜性,统计分析得到不同次生物质抗蚜阈值。单宁与总酚对麦长管蚜有明显增效作用,单宁与门布存在一定的增效作用,总酚与丁布有一定的拮抗作用。单宁酸、总酚、香豆素和单宁酸、儿茶素、香豆素、门布分别是抗麦长管蚜和禾谷缢管蚜的次生物质。     

禾谷缢管蚜体内保幼激素的变化趋势

为明确禾谷缢管蚜Rjopalosiphum padi 不同发育阶段体内保幼激素(ju-venile hormone,JH)的变化趋势,借助高效液相色谱(HPLC),确定了蚜虫JH测试方法,并对其JH进行了测定.结果表明:在若蚜阶段存在三种JH即JHⅠ、JHⅡ和JHⅢ;在成蚜阶段只能检测到JHⅢ.在整个发育过程中,JH变化趋势为虫龄越高,JH滴度越低,无翅3、4龄若蚜体内三种JH均极显著高于同期有翅若蚜.母代翅型对子代不同龄期若蚜JH滴度有明显影响.无翅成蚜后代1龄JH滴度极显著高于同期有翅成蚜的后代;2龄时,有翅成蚜的后代JH滴度骤然上升;有翅成蚜后代在2、3龄时JH滴度极显著高于同期无翅成蚜的后代.2龄之前是两种翅型母代的后代滴度变化的转折点,表明1～2龄若蚜期是禾谷缢管蚜翅型分化的关键时期和JH影响翅型分化的敏感龄期.     

吡虫啉对小麦上禾谷缢管蚜的生物活性及应用技术

通过室内测定和田间多点试验,明确了吡虫啉对小麦上禾谷缢管蚜[Rhopalosiphum padi(L.)]具有优异的生物活性,处理后48h的致死中浓度为0.11mg/L,40mg/L浓度处理麦株后22天的残留活性为89.9％;每hm~2用20％吡虫啉60～75g可以有效地防治小麦穗蚜的发生为害,持效期可达20天左右,用手动喷雾和弥雾具有同样的防治效果。田间施用吡虫啉可增产11％～18％。     

BYDV PREDICTOR: a simulation model to predict aphid arrival, epidemics of Barley yellow dwarf virus and yield losses in wheat crops in a Mediterranean-type environment

BYDV PREDICTOR, a simulation model, was developed to forecast aphid outbreaks and Barley yellow dwarf virus (BYDV) epidemics in wheat crops in the grainbelt region of southwest Australia, which has a Mediterranean-type climate. The model used daily rainfall and mean temperature to predict aphid ( Rhopalosiphum padi ) buildup in each locality before the commencement of the cereal-growing season in late autumn, and to forecast the timing of aphid immigration into crops. The introduction of BYDV by aphid immigrants, aphid buildup within the crop, spread of BYDV, and yield losses were predicted for different sowing dates. The model simulations were validated with 10 years' field data from five different sites in the grainbelt, representing a wide range of scenarios. When first aphid arrival dates ranging from 1 June to 2 September were compared with predictions, 65% of the variation between sites and years was explained. Progress curves for the predicted percentage of plants infected with the serotype BYDV-PAV closely resembled the starting point and shape of those recorded in 14 out of 18 scenarios. Sensitivity analysis confirmed that the combination of a high proportion of immigrants vectoring BYDV, early sowing of crops and early start to aphid arrival relative to sowing date led to the most BYDV spread and greatest yield loss. The model was incorporated into a decision support system used by farmers in targeting sprays against aphids to prevent virus spread in autumn and winter. BYDV PREDICTOR could serve as a template for modelling similar virus/aphid vector pathosystems in other regions of the world, especially those with Mediterranean-type climates.     

中国西北地区麦二叉蚜与禾谷缢管蚜对小麦黄矮病传毒能力的分析

为了研究中国西北地区蚜虫对小麦黄矮病的传毒能力,为西北地区防治小麦黄矮病提供参考依据,常温条件下在温室大棚用盆栽小麦做传毒试验,以接种不同数量有毒蚜的小麦苗作为处理,接无毒蚜的小麦苗作为对照.传毒3 d后,在接种麦苗上喷洒药剂彻底杀死蚜虫,充分发病后观察记录小麦黄矮病的发病情况.结果表明,中国西北地区小麦黄矮病的优势介体是麦二叉蚜,但禾谷缢管蚜的传毒能力比以前有所提高.关中地区禾谷缢管蚜的传毒力高于河西地区禾谷缢管蚜的传毒力;三个地区(关中地区、渭北地区、河西地区)麦二叉蚜的传毒力都较高,差别不明显.三个地区两种麦蚜的成蚜传毒力普遍高于其若蚜的传毒力.     

High variation in frequency of infection by endophytes in cultivars of meadow fescue in Finland

Systemic and asymptomatic Neotyphodium fungal endophytes infect numerous species of the Poaceae. The frequencies of Neotyphodium endophyte infection in Finland were investigated among and within seven Nordic cultivars of meadow fescue, Schedonorus pratensis (Huds.) P. Beauv., which is a widely grown pasture and forage grass species in Scandinavia. The cultivars were Kasper, Salten, Antti, Fure, Ilmari, Inkeri and Kalevi. Frequencies of infection of cultivars varied from endophyte-free cultivar Fure to highly infected cultivar Inkeri [mean (standard deviation of mean) of 0·95 (0·023)]. Mean frequencies of infection of three cultivars remained lower than 0·10, and two of the cultivars, Kasper and Salten, were intermediately infected. In most of the cultivars, frequencies of infection varied only slightly among seed lots. In cultivar Kasper, however, the frequency of endophyte infection was highly variable (0–0·96) among the 45 seed lots examined. The relative importance of cultivar, seed lot and infection by Neotyphodium endophyte to the aphid Rhopalosiphum padi L. was studied experimentally, using both endophyte-free and endophyte-infected plants of four seed lots of the two intermediately infected cultivars. Endophyte infection increased plant resistance to R. padi , overriding the influences of seed lot and cultivar. It is proposed that variation caused by endophyte infections in cultivars of meadow fescue should be taken into account in assessing plant breeding programmes in Europe.     

麦蚜迁飞的研究进展

麦蚜分布广、食性杂、繁殖力强,是世界性的农业害虫。在此,从麦蚜的田间网捕、传毒能力、飞行磨测试以及分子遗传学研究等七方面介绍了麦蚜迁飞行为的主要研究进展,讨论了麦蚜迁飞的生态意义,可能的蚜源基地及需要进一步研究的问题。     

高抗虫玉米内生真菌对玉米蚜生长、繁殖及取食选择的影响

植物内生菌普遍存在于健康植物组织或器官内，可通过自身的代谢产物或信号传导作用促进植物生长、增强宿主植物抗病虫性、抗胁迫性等。为明确前期筛选出的高抗虫玉米内生真菌YC1、GX5、YB8、YB15对玉米蚜生长繁殖的影响，室内测定了玉米蚜取食不同菌株种子处理的玉米后存活、繁殖以及对接种不同菌株玉米的取食选择。结果显示，取食菌株处理玉米后，玉米蚜产雌历期显著低于对照；产雌量、净增殖率、世代平均寿命、内禀增长力、周限增长率均低于对照，但差异不显著。取食选择试验结果表明，选择YC1、GX5、YB8、YB15处理组玉米的玉米蚜比例分别为17.52%、19.02%、19.34%和18.84%，均显著低于对照组25.28%。说明这4株玉米内生真菌对玉米蚜的生长繁殖有不利影响，且对玉米蚜有趋避作用。