共查询到20条相似文献，搜索用时 62 毫秒
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玉米耕葵粉蚧(Trionymus agrealisWang et Zhang)是我省玉米新发现的一种害虫。80年代末在赵县、满城玉米田内发现,目前已扩散到保定、廊坊、唐山等地。今年我市在安次区、固安、永清、香河等县点片发生,发生面积10万亩左右。成为我市玉米上的主要害虫之一。玉米耕葵粉蚧不但为害玉米,还为害小麦、高粱等禾本科作物和杂草。1 为害及发生1.1 为害玉米耕葵粉蚧以若虫和雌成虫群体在地表以下玉米、小麦茎基部吸食汁液,进行为害造成小麦、玉米叶片发黄,生长缓慢或枯萎。玉米受害严重时茎基变粗,不能结 相似文献
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玉米耕葵粉蚧是玉米的新害虫 ,目前已在河北省邢台、保定、廊坊、唐山等地发生为害 ,并有逐年加重为害的趋势。 1 999年廊坊市的永清县、安次区、固安县、香河县发生为害严重 ,造成大面积夏玉米苗期叶片叶脉发黄 ,幼苗生长缓慢或枯萎 ,植株矮小细弱 ,甚至枯死。 2 0 0 0年 7月初部分夏玉米地块已出现被害 ,受害面积不断扩大。玉米耕葵粉蚧属粉蚧科粉蚧属。在廊坊市 1ａ发生 3代 ,以第二代为害夏玉米最为严重。第二代发生期为 6月下旬至 8月上旬。此时正值夏玉米幼苗期 ,耕葵粉蚧卵开始孵化 ,若虫聚集在夏玉米茎根基部和近地面叶鞘内吸取汁液… 相似文献
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我县是全国沙田柚生产基地县,目前已种植沙田柚12万亩。在为害沙田柚的各种害虫中,最主要的是蚧类,经近年的调查鉴定,主要种类有红圆蚧、褐圆蚧、矢尖蚧、糠片蚧、黑点蚧、吹绵蚧、堆粉蚧等,其中分布最广、发生为害最严重的是红圆蚧[Aonidiella aurantiiMaskell)]。它以幼蚧和雌成蚧终生固定在沙田柚的枝条、叶片和果实上吸食汁液,特别是为害内膛挂果枝条致枯死而严重影响挂果。红圆蚧一般在3年生树龄以上的柚树上发生为害, 相似文献
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大豆根绒粉蚧研究简报山东省东平县农委（２７１５００）王玉堂大豆根绒粉蚧ＥｒｉｏｃｏｃｃｕｓＳＰ．属同翅目，蚧总科，绒粉蚧属，是寄生大豆根部的一种新害虫。作者在王体誉（１９８１）首次报道的基础上，对其生物学特性和防治方法又进行了深入研究，简报如下１为害... 相似文献
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针对毁林新害虫花椒绵粉蚧的发生为害,重点研究了其在山西省的发生分布、生活习性、发生规律和综合防治技术措施。 相似文献
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新疆奇台县近42a气候变化特征分析 总被引：5，自引：1，他引：4
根据新疆奇台县气象站的气温及降水资料,利用线性趋势函数及M ann-kendall突变检测法分析了该地区近42年的气候变化。结果表明:年平均气温与极端最低气温均呈上升趋势,而极端最高气温呈下降趋势;年降水量呈上升趋势。从季节变化来看,除夏季平均气温呈下降趋势,其它各季平均气温均呈上升趋势,其中以冬季增幅最大,秋季次之;各季降水均呈上升趋势,其中以夏季增幅最大,冬季次之。年平均气温未发生突变,而年降水量在1984年发生由少向多的突变。对气温和降水的异常分析得出,暖温年多发生在上世纪80年代后,冷温年多发生在上世纪60、70年代;多雨年主要在近20年,少雨年则多在上世纪60、70年代。此外,该县近42 a来增暖幅度小于全疆和北疆;增湿幅度大于全疆,小于北疆。 相似文献
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综述了我国苜蓿主要病害的分布和危害、病原学、发生规律、抗性种质材料的遗传筛选和鉴定及综合防治等方面的主要研究进展,并提出了今后的研究方向和发展目标。 相似文献
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Cees Waalwijk Pieter Kastelein Ineke de Vries Zoltan Kerényi Theo van der Lee Thamara Hesselink Jürgen Köhl Gert Kema 《European journal of plant pathology / European Foundation for Plant Pathology》2003,109(7):743-754
The re-emergence of fusarium head blight throughout the world and especially in Western Europe prompted a survey of the situation in the Netherlands. To allow for a high throughput screening of large numbers of samples, a diagnostic PCR method was developed to detect the most common species of Fusarium occurring on wheat. Seven primer pairs were tested for their ability to identify isolates of Fusarium avenaceum, F. culmorum, F. graminearum, F. poae, F. proliferatum and Microdochium nivale var. majus and M. nivale var. nivale. Each primer pair only generated a PCR product with the corresponding Fusarium species and all PCR fragments had different molecular sizes. This allowed the generation of these amplicons using a mixture of all seven primer pairs. The robustness of this multiplex PCR encouraged us to screen a large series of isolates collected in 2000 and 2001. In both years 40 fields were sampled leading to a collection of 209 isolates from 2000 and 145 isolates from 2001. The results of the multiplex PCR demonstrated that F. graminearum was the most abundant species in the Fusarium complex on wheat in both years. This is in sharp contrast to reports from the 1980s and early 1990s, which found F. culmorum as the predominant species. Primers derived from the tri7 and tri13 genes, which are implicated in the acetylation and oxygenation of the C-4 atom of the backbone of the trichothecene molecule, were used to discriminate between deoxynivalenol and nivalenol (NIV) producers. The populations of F. culmorum and F. graminearum both showed a slight increase in NIV-producers in 2001. 相似文献
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弹状病毒含有单链负义RNA基因组,寄主范围比较广泛,能侵染无脊椎动物、脊椎动物以及植物等寄主,对人类的健康、农作物产量和自然生态系统造成严重威胁。植物弹状病毒主要根据复制场所分为细胞质弹状病毒属Cytorhabdovirus和细胞核弹状病毒属Nucleorhabdovirus,其基因组由单股负链RNA组成。此外,Dichorhavirus和Varicosavirus病毒属是两个新鉴定的植物弹状病毒属,其特征是具有二分体基因组。本文着重介绍危害我国农作物的几类植物弹状病毒,对它们的病理学、病害流行、基因组信息以及传播媒介进行概述,为中国植物弹状病毒病害的研究提供理论依据。 相似文献
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Variation in pesticide residues in space and time has not been investigated systematically in spite of the large variability found at single scales (e.g. between trees or orchards). Information on variability at different scales will support the development of sampling methods and more reliable prediction of residues. Experiments were conducted to quantify the spatiotemporal variability in initial spray deposit on apple leaves and fruit using a substitute tracer (zinc EDTA chelate). Five hierarchical spatial scales were defined as (1) between orchards, (2) between plots within an orchard, (3) between trees within a plot, (4) between zones within a tree and (5) between leaves/fruit within a zone. Similarly, two temporal scales were defined as (1) between applications within a single year and (2) between years. The initial zinc concentration was approximately log-normally distributed; the variability in initial deposit concentration was greater on leaves than on fruit. The average initial zinc deposition was significantly greater in the top and outside zones than in the middle zones within individual trees. The most important scale for driving residue variability is the within-zone unit-to-unit variation, contributing to 71 and 49% of the observed variability for leaf and fruit samples respectively. Variability at other scales was related to the variation in the tree architecture. The results indicated that stratified sampling on the basis of within-tree zone structures, with the effort focused on within-zone sampling, should be used for the determination of pesticide residues. 相似文献