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新疆阿拉尔垦区棉田杂草名录 总被引:1,自引:0,他引:1
新疆阿拉尔垦区位于塔里木盆地的西北部边缘 ,塔里木河自西向东流经本垦区 ,地势开阔平坦 ,灌溉条件良好 ,农业气候资源丰富 ,是盛产棉花的优良基地。杂草的危害 ,常造成棉花减产 ,危害重的地块甚至形成草荒。由于对棉田杂草的种类及发生情况缺乏全面系统的了解 ,常使化学除草效果不佳。对此我们于 1996年开始对阿拉尔垦区棉田杂草进行了调查研究。阿拉尔垦区棉田杂草共有6 0种 ,隶属于 19科。由于连年使用氟乐灵 ,棉田中禾本科杂草种类逐渐减少 ,危害逐年减轻 ,而阔叶杂草危害逐年加重。其中一些种类如稗、狗尾草、芦苇、灰绿黎、黎、田旋… 相似文献
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新疆伊犁河谷大豆田杂草种类有7科13种,其中发生普遍、危害严重的优势种有灰绿藜、田旋花、稗、画眉草、金色狗尾草5种。杂草的防除,以精选种子、使用腐熟有机肥、合理栽培、轮作倒茬等农业防除措施为基础,化学防除为主要手段,可把杂草危害控制在最低程度。 相似文献
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吉林省西北部地区向日葵田杂草调查初报 总被引:1,自引:0,他引:1
采用倒置“W”9点取样法,对吉林省西北部地区向日葵田杂草进行了调查.结果表明,该地区向日葵田杂草有19科49种,其中阔叶杂草16科36种占73.5%,禾本科杂草10种占20.4%,其他3种(列当科1种、木贼科2种)占6.1%.一年生杂草35种占71.4%,一年生或越(多)年生杂草3种占6.1%,多年生杂草11种占22.4%.相对多度达10以上的杂草有4科11种,按相对多度由高到低的次序排列,分别为列当、藜、刺藜、反枝苋、稗草、野稷、芦苇、苍耳、狗尾草、苣荬菜、虎尾草,可视为吉林省西北部地区向日葵田的主要杂草. 相似文献
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一、棉田杂草种类及危害 喀什地区棉田,主要杂草有芦苇、稗草、狗尾草、灰黎、田旋花、苍耳、苦苣菜、苦豆子、草木栖及辣酱草等。稗草和灰黎在棉田出土危害有两个高峰期:第一个高峰期为4月下旬至5月中旬;第二个高峰期在6月底至7月下旬。芦苇出土危害一般在4月底至秋后。棉田杂草对棉花的生长、发育、产量及经济品质危 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