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直播水稻产量高、种植方便，已成为青浦地区水稻的主要栽培方式。栽培面积的比例，已从１９９６年的５５％扩大到２０００年的８７％，目前已达１．７４万ｈｍ２。直播水稻一般于６月上旬播种，１０月底开始收割，在大田的生长期较长，且分蘖多、密度高、田间郁闭，较常规移栽稻害虫发生早、为害重，其发生规律有很大差异。每年均有１～２种害虫发生程度达偏重至大发生。作者经多年调查研究，现将主要害虫发生特点及防治技术总结如下：１主要害虫发生特点１．１稻象甲已成为直播水稻的主要害虫之一，为害重的田块会造成毁苗而重播。该虫以幼… 相似文献
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"两迁"害虫是水稻的主要害虫,近几年来在我区水稻发生程度呈暴发的态势,2008年已形成暴发的严峻局面,对水稻生产已构成严重威胁.全区早、中、晚稻种植面积分别为户2 333.33hm2、3 000hm2、2 333.33hm2,共计7 666.66hm2. 相似文献
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稻杆潜蝇危害我区水稻,自１９８６年首次在堡子镇发现以来,危害程度逐年加重。１９９８年发生面积已达２５万亩,占水稻种植面积的４５％。由于该害虫是近年发生的水稻害虫,没有引起广大农民的足够重视,防治效果差。现引进并筛选３％呋喃丹颗粒剂（美国ＦＭＣ公司生产... 相似文献
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<正>2009年水稻"两迁"害虫稻白背飞虱、稻纵卷叶螟大量迁入黔东南州为害水稻。至6月底,两虫累计发生面积已达到14.2万hm2次,水稻稻瘟病、纹枯病、螟虫发生面积也呈上升态势。面对以水稻"两迁"害虫为主的病虫害发生的严峻形势,州农业局及各县市农业局迅速行动,采取积极有效措施,深入田间地头指导防治,全力抓好防控工作,水稻病虫害得到全面控制,确保了全州水稻生产获得丰收。 相似文献
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泸州地区稻飞虱监测预警及控制对策 总被引：2，自引：1，他引：2
稻飞虱是四川南部稻区水稻生产上为害最严重的迁飞性害虫之一。泸州是四川稻飞虱的常发区,重灾区。20世纪80年代前,本地区稻飞虱以褐飞虱为主,间隙暴发为害。自20世纪80年代初始,白背飞虱种群数量不断上升,已取代褐飞虱成为本地区稻飞虱的主要虫种,暴发频率显著增加,到90年代几乎间隔1年大发生1次。2000年后,泸州南部稻区(叙永县、古蔺县及合江县南部)白背飞虱几乎年年偏重至大发生(表1),已成为影响本地区水稻生产的重要经济害虫,必须加强监测控制,减轻其为害损失。 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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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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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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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
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河北省小麦田杂草防治技术进展 总被引：3，自引：0，他引：3
小麦是河北省第一大种植作物 ,常年种植面积2 4 6 .7万hm2 左右。随着农民种植水平、农业机械化程度的不断提高 ,麦田杂草成为制约小麦高产的主要障碍之一。全省小麦田杂草的发生面积超过2 13 3万hm2 ,每年因草害造成小麦产量损失 10 %～15 % ,重发田块高达 30 %～ 5 0 %。为了提高杂草的防除水平 ,河北省植物保护总站从 1998年在农业厅立项实施了小麦田杂草无害化治理技术与推广 ,几年来在广大植保技术人员的共同努力下 ,经过大量试验、示范以及组织推广 ,使麦田杂草的除治工作有了较大进步。1 基本摸清了麦田常见杂草种类和群落分布1.1 … 相似文献