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枣阳市2006年水稻种植面积4·97万hm2,稻飞虱发生是继1987年、1991年后又一个大发生年,第3代、第4代稻飞虱发生面积累计达7·67万hm2,挽回稻谷损失18·65万t,笔者对其发生特点原因及防治进行观察分析如下:1发生特点1·1发生期早2006年我市第3代稻飞虱低龄若虫高峰期为7月20~30日,第4代稻飞虱为8月15~25日,比1987年、1991年分别早5d、7d。1·2发生数量多第3代稻飞虱发生高峰期平均百蔸虫量为2300头,最高达8 000头,第4代稻飞虱百蔸平均为6 050头,最高达1·5万头,比1987年高8·18%,与1991年持平。1·3短翅型成虫数量多第3代稻飞虱短翅型成虫百… 相似文献
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稻飞虱是钦北区水稻主要害虫之一,以白背飞虱和褐飞虱为主,近年来,稻飞虱发生日趋严重,而且有提前发生为害的趋势,2005年由于虫源、气候等因素的影响,造成钦北区第2代稻飞虱局部大发生,发生早、面积大、数量多,为近年来所少见。通过对其局部大发生原因的分析,可为今后的测报和防治提供依据。1发生特点1·1发生范围广,受害面积大2005年钦北区第2代稻飞虱发生程度3(4)级,发生面积为9 300hm2,同比增16·7%,比前5a的平均值增22·8%,发生面积占种植面积52·9%,同比增32·3%,比前5a的平均值增41·1%;虽经大力防治,防治面积达8 000hm2,为害损失基本… 相似文献
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2006年武汉市水稻稻飞虱特大发生,虫量之大、来势之猛、面积之广、程度之重、时间之长为历史罕见,发生面积13.8万hm2次,防治面积54万hm2次。其发生特点:一是迁入早。5月25日见虫,较常年偏早7~10d;二是面积大。第3代发生面积占种植面积的60%,第4代、第5代发生面积占种植面积的90 相似文献
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稻飞虱是田东县水稻常发性、普发性、重发性害虫,近10 a来主害代发生都在3级以上,给水稻生产造成严重威胁.根据田东县历年稻飞虱发生为害情况与气候、苗情、田间管理、防治措施等的关系,探讨提高稻飞虱防治效果的最佳方法和对策,最大限度地降低稻飞虱对水稻生产的危害. 相似文献
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稻飞虱是崇阳县水稻生产上的主要害虫之一。因近年来,连续大暴发,对农业生产和生态环境造成严重威胁,直接影响了粮食增产、农业增效、农民增收目标的实现。总结分析稻飞虱的发生特点、形成原因及对其它地区的影响,对研究因水稻种植结构、品种调整稻飞虱新的发生为害特点,具有十分重要的意义。1稻飞虱发生危害特点1.1各代田间发生期稻飞虱从4月下旬或5月上旬迁入我县,一年内在水稻上发生不完整5代,个别年份发生6代。危害盛期在7月上旬至10月中旬,混栽区中稻和双季稻晚稻受害最为严重。在早、中、晚稻混栽区,第1代长翅型成虫盛期在5月中旬,第2… 相似文献
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河池市稻飞虱的发生与防治简报 总被引:1,自引:0,他引:1
在河池市危害水稻的稻飞虱主要有白背飞虱、褐飞虱。早春主要虫源由东南亚随西南气流迁入,秋季随东北气流由北回迁。褐飞虱和白背飞虱在河池一年可发生7~8代,其中主要危害代为第2~6代,对水稻造成危害重、损失大,不防治的田块可颗粒无收。第1代发生在3月份,第2代发生在4~5月间,第3、4代发生在6月中旬至7月上旬,这时正值早稻孕穗、抽穗、灌浆期,第5、6代发生在8月下旬至9月中旬或10月上旬, 相似文献
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1 水稻病虫 1.1 稻飞虱、稻纵卷叶螟 预计第2代稻飞虱4级发生(中等偏重),鄂东局部5级(大发生);第3代、第4代、第5代稻飞虱全省5级.预计第2代稻纵卷叶螟4级发生,局部5级,第3代、第4代稻纵全省5级. 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