The effect of oviposition experience of adult Microplitis pallidipes parasitoids on discrimination between nucleopolyhedrovirus-infected and healthy Spodoptera litura larvae

Using multiple pest-mortality sources is a basic tenet of IPM, but they may not always be compatible. To that end, we examined compatibility of parasitism and nucleopolyhedrovirus (NPV) infected. Specifically, we examined the effects of prior oviposition experience by Microplitis pallidipes on its ability to distinguish NPV-infected from healthy larvae of Spodoptera litura. We found that time spent searching for hosts was significantly lower, while the number of attacks, percentage of first attacks, and parasitism rate were all significantly higher in healthy versus virus-infected hosts for parasitoids that had experienced healthy hosts. Meanwhile, parasitoids that had experienced infected hosts spent significantly more time searching for infected hosts starting on day 2. For these parasitoids, the number of attacks, percentage of first attacks, and parasitism rate were all significantly lower from day 2 in virus-infected versus healthy larvae. We found no significant differences between parasitoids without experience versus ones experienced with infected hosts in search time for infected hosts, number of infected host attacks, or percentage of first attacks on infected hosts. In comparison, parasitoids that had experienced healthy hosts spent less time searching for healthy hosts than parasitoids without experience, and displayed a higher frequency of attack on healthy hosts and a higher percentage of first attacks on healthy hosts. Experience with healthy larvae aided parasitoids in distinguishing healthy from virus-infected larvae, but experience with virus-infected larvae did not convey the same discrimination. This information provides a better understanding of how to integrate NPV applications with naturally occurring parasitism for this pest in crops.     

RNA interference and its application in plants

RNA interference （RNAi）, a process that inhibits gene expression by the double-stranded RNA （dsRNA）, causes the degradation of target messenger RNA molecules. RNAi exists in almost all organisms. We review the recent history of RNAi studies, RNAi molecular mechanisms, characteristics and RNAi applications in higher plants. At the same time, the prospect of RNAi applications in functional genomics and genetic improvement of higher plants and possible future problems and possibilities are also discussed.     

RNAi的抑制物及其应用

在植物、动物中广泛存在的一种基因调控现象,RNAi现象是通过调控RNA的分子水平来抑制基因表达。被认为是一种抑制病毒性复制和转座子活动的抗御机制。在此过程中,侵染型病毒为了能够不被这种机制干扰抑制,继续在寄主体内生存、繁殖,则产生了一种反抗御机制———即产生抑制蛋白来对抗转录后基因沉默。本文集中讨论了当前已知的植物病毒编码的沉默抑制物。它们在抑制途径中的不同阶段干扰沉默,这些抑制物已成为一种有力的工具来帮助了解植物中RNA沉默的机制,并在研究基因功能等方面有着广泛的应用前景。     

杨树幼树主要害虫及其防治

详细介绍杨树幼树主要害虫的种类、形态特征、生活习性,并提出了有效的防治措施。     

利用蛹体宽度测算赤松毛虫产卵量的研究

赤松毛虫DendrolimusspectabilisButler蛹体宽度与其产卵量成正比;回归式y=-1204+1362x,r=0.95,并编制了赤松毛虫蛹体宽度与产卵量查定表,准确率达97.21%,可供预测预报参考.     

黄脊竹蝗产卵地与其生态因素关系的调查研究

黄脊竹蝗是楠竹的严重食叶害虫,防治黄脊竹蝗的关键在于顺利地找到产卵地,以便在产卵地内治理孵化出土跳蝻或已上竹尚未分散危害的1～2龄跳蝻。本文报道成虫产卵规律以及与9种生态因素的关系。其产卵地必须具备综合多生态因素,而光照是最重要的因素。只有竹林和植被稀疏,地面透光度大,光照强的地方才是成虫产卵的首选之地。     

皱大球蚧产卵与卵期预测预报的研究

皱大球蚧是国槐等多种园林树木的重要害虫。准确预报其发生量与若虫孵化期是防治成败的关键。 1999年 5月对产卵末期虫体重、体长及产卵量的测定和室内恒温、变温饲养的研究表明产卵量与体重、体长相关方程式分别为 :Y1=- 2 0 0 7 6 782 + 76 85 1 3738X1,Y2 =- 12 4 2 6 0 813+ 2 6 99 16 6 4X2 ,卵发育起点温度C =13 5 1± 0 5 0℃或C =13 2 1± 0 0 9℃ ;有效积温K =187 4 7±8 79DD或K =192 4 8± 1 5 9DD。经 2 0 0 0年检验与实际符合     

Observation of interference effects in air-coupled ultrasonic inspection of wood-based panels

The air-coupled ultrasonic inspection method is a widely applied non-destructive measuring technique in the wood-based panel industry. The technology is mainly applied to detect panel delaminations by analyzing the transmitted signal. Recent research deals with the use of ultrasonic techniques not only for the qualitative but also for the quantitative characterization of wood-based panels. To achieve a fundamental understanding of the behavior of ultrasonic waves in wooden panels, it is necessary to study the mechanisms that affect ultrasonic transmission and velocity during testing. Impedance and attenuation effects have been examined in previous studies. This article focuses on the interferences of ultrasonic waves. The interferences can be detected in experiments where the ultrasonic transmission is tested against the panel thickness. The results are verified with a mathematical model that explains the interferences due to multiple reflections inside the tested panels. By fitting the experimental data to the model predictions, the ultrasonic velocity and attenuation can be determined. So far, interference effects have not been considered for the non-destructive testing of wood-based panels. This research is a contribution to a better understanding of the mechanisms influencing the air-coupled ultrasonic methods.     

青杨天牛成虫交配刻槽产卵习性初步研究

采用室内养虫笼饲养法和林间套网袋饲养法观察青杨天牛Saperda populnea成虫的交配、刻槽、产卵等习性,发现雌雄交尾时间可持续10~240 min,平均约180 min;有重复交配现象,重复交配可达2~10次;每次交配持续时间为2~30 s。雌虫在寄主枝条上刻槽呈马蹄形,每次刻槽需2~3 min,环绕枝条一周以2个刻槽常见。雌虫刻槽后直接产卵,每刻槽产卵1粒。产卵期长短和产卵量大小取决于雌虫个体寿命长短,且雌成虫有较强的生殖能力。     

松褐天牛迁移迁飞及产卵规律初探

本文通过实地观察、研究,发现松褐天牛具有向东南方迁飞概率较高,并喜在三面环山的小盆地、山丘地,或多山相连的地段活动,一般多在树皮薄、胸径12～18cm松树上集中产卵,其产卵刻槽大多位于松树树干3 m以下的特性.掌握这些习性,有利于制定松褐天牛防治方案,并为具体防治措施的实施提供了方便.     

Density and nitrogen effects on interference and economic threshold of common lambsquarters in wheat

Common lambsquarters (CL) constitutes about 50 % of the total weed population in many wheat fields of the northern and central India. It causes considerable wheat yield losses. Its interference is highly influenced by nitrogen (N). Information on its density effect in response to N, and economic threshold (ET) will be useful for its effective management. This experiment was designed to evaluate and compare the interference of CL in response to N with that of natural weed infestations; and to determine its ET in wheat. It was observed that the natural weed infestation including CL, and a pure stand of 128 CL plants/m² were more competitive, causing greater reductions in wheat growth and yield than other CL densities. In the absence of CL, the natural weed infestation was less competitive. The natural weed infestation including CL, and the pure stand densities of 128 and 64 CL/m² inflicted more yield losses at 120 than 60 kg N/ha. But, at lower densities up to 32 CL/m², increasing N levels favoured wheat more, resulting in greater crop-weed balance at 120 than at 60 kg N/ha. The ET, 6–7 CL/m², would help in making decisions for CL management and fitting models. It can be approximated for other similar locations. This ET takes several production factors into account and would be more economical than what was determined based on only yield losses. The ET-based control would reduce future CL/weed populations by preventing seed bank build-up in soil, and rationalize herbicide use through tailoring of doses.     

悬铃木方翅网蝽风险分析评估

悬铃木方翅网蝽Corythucha ciliate Say是新入侵我国的有害生物。本文根据悬铃木方翅网蝽的国内分布状况、潜在经济危害性、寄主植物的经济重要性、传播扩散的可能性和危险性管理难度等方面对其进行了风险分析评估,结果表明悬铃木方翅网蝽为我国风险中度偏高的有害生物,对其要进行谨慎检疫监理。     

双条杉天牛产卵量与卵期预测预报的研究

双条杉天牛是柏类园林树木的重要害虫之一 ,影响绿化成果和木材工艺价值 ,准确测报其发生量与幼虫孵化期 ,是防治成败的关键。通过 2 0 0 0～ 2 0 0 1年 2～ 5月重复试验 ,得出产卵量与鞘翅长、肩宽及鞘翅长与肩宽积及体重相关方程式分别为 :y1=- 12 9 78+ 2 1 4 3x1,n =4 0 ,r1=0 7784 >r0 0 1=0 4 0 3;y2 =- 10 2 86 + 4 1 2 2x2 ,r2 =0 80 14 >r0 0 1=0 4 0 3;y3=- 2 6 35 + 2 4 2x3,r3=0 80 6 3>r0 0 1=0 4 0 3;y4 =- 2 81+ 74 1 72x4 ,r4 =0 84 0 4 >r0 0 1=0 4 0 3。卵发育起点温度 :C=9 13± 1 2 0 (℃ )或C =9 0 5± 0 82 (℃ )有效积温K =92 83± 6 6 4(DD)或K =6 8 6 5± 8 15(DD)。经 2 0 0 2年应用及检验与实际符合。     

4种杀虫剂对枸杞红瘿蚊幼虫的药效比较

为了提高对枸杞红瘿蚊幼虫的化学防治效果,选用5%的啶虫脒(EC)、20%的噻虫嗪(WG)、10%的吡虫啉(WP)和1.8%阿维菌素(EC)这4种具有内吸性或渗透性的杀虫剂进行室内和田间药效试验。试验结果表明:5%的啶虫脒2 000倍液、20%的噻虫嗪4 000倍液和10%的吡虫啉2 000倍液对枸杞果内红瘿蚊幼虫均有显著的防治效果,施药后第4天,室内校正防治效果分别为99.08%、98.43%和99.64%,田间校正防治效果分别为98.71%、98.58%和98.45%;而1.8%阿维菌素2 000倍液的防治效果较差,施药后第4天,室内和田间校正防治效果分别为42.27%和38.02%,其与啶虫脒、噻虫嗪和吡虫啉防治效果的差异达到了极显著水平。室内和田间药效试验结果表现一致,该结果能够为生产上枸杞红瘿蚊幼虫的化学防治起到指导作用。     

外来有害生物——悬铃木网蝽的发生与防治

悬铃木网蝽（Corythucha ciliata Say）,又名悬铃木方翅网蝽、悬铃木白翅网蝽,系国内新近发现的外来有害生物。本文对该害虫的分类地位、形态特征、危害特点、地理分布与寄主范围、生物学特性及其防治方法进行了简要介绍,指出了目前亟待解决的几个问题。     

黄褐天幕毛虫幼虫食叶量观测及防治指标的测定

该文探讨了荒漠地区黄褐天幕毛虫ＭａｌａｃｏｓｏｍａｎｅｕｓｔｒｉａｔｅｓｔａｃｅａＭｏｔｓｃｈｕｌ－ｓｋｙ幼虫的食叶量。人工模拟不同摘叶强度对胡杨高、径生长量的方差分析及多重比较，Ｆ＞Ｆ０．０１，Ｄ＞Ｄ＊，摘叶３０％、５０％与摘叶１００％之间高、径生长量差异极显著。掌握了胡杨１００ｃｍ标准枝承受的害虫幼虫数及允许受害密度，建立了胡杨幼树单株材积生长量的一元回归方程：Ｙ＝２７．６８１８１＋２５１４２．３５９５７Ｘ。提出天幕毛虫幼虫防治指标：３．４头／１００ｃｍ标准枝，投入防治费用等于挽回经济损失的危害比例为３３．４％，即害虫幼虫危害大于摘叶３３．４％以上，则应立即防治。     

大量分离松材线虫幼虫及获得无菌幼虫的方法

利用松材线虫成虫和幼虫在比重和运动性方面的差异,通过在0.3%羧甲基纤维素钠盐溶液中沉降而得到分离。并在4℃条件下用3%H2O2处理松材线虫幼虫60 min而得到无菌幼虫。     

Relationships between the emergence and oviposition of ectoparasitoid Spathius agrili Yang and its host emerald ash borer, Agrilus planipennis Fairmaire

Emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), (= A. marcopoli Obenberger), is an important bark beetle attacking ash trees (Fraxinus spp.). It is very difficult to detect and control because of its highly concealed life history. This pest mainly distributed in partial Asian countries (China, Japan, Korea, Mongolia) and Far East Russia, while in China it presented in Heilongjiang, Jilin, Liaoning, Shandong, Inner Mongolia, Hebei, Taiwan Provinces and Tianjin City, etc. The important timber species F. mandshurica and gardening tree F. velutina were damaged severely in northern China. Spathius agrili Yang (Hymenoptera: Braconidae) is an important ectoparasitic wasp of the EAB larvae. This parasitoid has the potential to use as an excellent biological control agent for suppressing populations of EAB. The differences of emergence date between overwintered S. agrili and its host, parasitism rates at different periods, relations between parasitism rates and host densities, and relationships between ovipositions of braconid wasp and body sizes of host larvae were studied using methods of regular surveys in forests and observations in laboratory. Results revealed that the emergence of S. agrili was more than one month later than that of its host. It suggests good synchrony between parasitoid emergence and host availability. The overwintered S. agrili emerged from mid June to mid August with the peak in July in 2003, and it lasted from late May till late July with the peak during late June to early July in 2004. While the EAB emergence period ranged from mid May to late May in 2003, it ranged from mid April to mid May in 2004 (in laboratory). The emergence date of parasitoid asynchronously inosculated with the optimum developmental instars of the earliest host larvae, which was the result of a long-term co-evolution between the two species. It was also suggested that the parasitoid S. agrili could be a specialized natural enemy for EAB. The natural parasitism rates on the whole gradually increased in field with time. The body sizes of host larvae, i.e. larval instar, affected the decision of parasitoid S. agrili to lay eggs or not. Under natural conditions, this parasitoid usually oviposited only on those host larvae with a prontum and body width more than 1.5 mm, and a body length in excess of 12 mm, i.e. the third or fourth instar larvae. These findings would consequentially contribute to the further successfully biological control of the trunk borer. __________ Translated from Acta Ecologica Sinica, 2006, 26(4): 1,103–1,109 [译自: 生态学报]     

绿僵菌MS01菌株的生物学特性及在不同温湿度下对光肩星天牛幼虫的致病力

光肩星天牛(Anoplophora glabripennis)是我国重要的多食性蛀干害虫,已造成经济、生态、社会效益的重大损失(张星耀等,2003;萧刚柔,1992),长期以来,我国投入了大量的人力物力用于防治光肩星天牛(孙福在等,1997;张波等,1999;张永安等,2003),但对光肩星天牛等害虫的有效生物防治方法并不多.     

利用管氏肿腿蜂防治松幽天牛幼虫试验

松幽天牛Asemum amurense Kraatz是典型的次期性蛀干蛀根害虫,也是松材线虫的传播媒介昆虫之一,严重威胁着林间长势衰弱的马尾松Pinus massoniana。本研究调查松幽天牛的危害情况,按照1∶1,1∶2,1∶3,1∶4的虫蜂比于室内外分别接种管氏肿腿蜂Sclerodermus guani Xiao et Wu防治松幽天牛低龄幼虫,并筛选接种最适虫蜂比例。结果表明:松幽天牛主要危害衰弱木、松褐天牛Monochamus alternatus危害木和枯死木,平均虫口数量分别为27,27,70头/株,最多为152头/株,有虫株率为11.99%。室内试验中按虫蜂比为1∶3接种时,寄生成功率最高为60.00%。林间试验中按虫蜂比1∶4接种时,防治效果最好,校正虫口减退率为56.47%。