Management of nematodes and a stalk borer by increasing within-field sugarcane cultivar diversity   总被引：1，自引：0，他引：1  

P. Cadet  S. D. Berry  G. W. Leslie  V. W. Spaull 《Plant pathology》2007,56(3):526-535

The aim of this study was to determine whether an increase in plant diversity could modify the structure of the nematode community in favour of less pathogenic species and whether it affected the lepidopteran stalk borer, Eldana saccharina . Four sugarcane cultivars were planted either singly or as a mixture in the furrow. Nematodes were enumerated when the crops were 6 months old for five successive 10 to 13 month old crop cycles. Results showed that the mixture of cultivars had little significant impact on the overall abundance of the plant-parasitic or free-living nematodes. However, the nematode community structure within the mixture was slightly different to that observed on any single cultivar planted on its own and there was a higher than expected proportion of Helicotylenchus dihystera during the first three crops. With successive crops and in all treatments, there was an overall trend of increasing proportions of Meloidogyne javanica in the nematode community. However, the way that the change in the species-balance occurred in the mixed cultivar plots suggested a resistance to the evolving dominance of M. javanica . These results showed that sugarcane cultivars interacted within the rhizosphere when planted in a mixture because the observed nematode community in the mixture differed from that expected. The level of damage caused by E. saccharina was slightly lower in the mixture than expected from the actual cultivar composition.  相似文献   

除草剂对作物产生药害的原因及治理对策   总被引：3，自引：0，他引：3  

李香菊  杨殿贤  赵郁强  李咏军 《农药科学与管理》2007,28(3):39-44

本文论述了我国除草剂使用过程中作物产生药害的主要原因和除草剂药害的治理对策。提出:除草剂使用不合理,除草剂和作物本身的因素,异常的环境条件是药害产生的主要原因。杜绝假冒伪劣及不合格产品,加强除草剂试验、示范、推广工作,深化除草剂应用技术研究,加强农民用药技术水平培训是除草剂安全使用应解决的问题。  相似文献   

农田黑线姬鼠发生规律与防治技术   总被引：1，自引：0，他引：1  

王华弟 《植物保护学报》1998,25(2):181-186

１９８５￣１９９５年１０年监测结果表明,黑线姬鼠为浙江农田优势种,每年４￣５月和９￣１０月为繁殖高峰期,６月和１０￣１１月为数量高峰。冬前冬后密度基数,种群年龄结构,繁殖力,温度,降水,天敌和药剂防治是影响种群数量变动的主要因子及预测的依据。根据害鼠密度与稻麦为类损失率及经济允许水平,提出主害期控制的鼠密度指标为：大小麦２．７％￣４．４％,早稻４．６％￣６．７％,晚稻６．９％￣８．４％,防治指标为  相似文献   

乌兰布和荒漠人工绿洲小气候效应研究   总被引：7，自引：0，他引：7  

王君厚  周士威 《干旱区研究》1998,15(1):27-34

通过对乌兰布和荒漠东北边缘人工绿洲内和荒漠对照区各小气候因子连续１２年的同步观察,采用模糊综合评判方法,全面定量分析了防护森体系不同时期的小气候效应及变化规律,评价结果表明,绿洲防护要体系对各气象因子有前显的影响,特别是降低风速,抑制蒸发,提高空气湿度等方面尤为突出,综合小气候效应明显,１２年间效益值增加了０．７４６,增长率为３１％,绿洲防护林体系对小气候的改善作用各时期不同,从综合效益值来看,初  相似文献   

乌鲁木齐河流域土地灌溉系统的灰色决策模型研究     

付炜 《干旱区资源与环境》1998,12(1):75-82

本文以乌鲁木齐河流域为试验区,介绍了干旱区流域土地灌溉系统的多目标灰色决策模型的构造原理和方法。利用灰色控制系统的理论和方法建立了灰色优势分析模型,并以该模型为基础建造了多目标灰色决策分析模型。对最优局势的效果测度与综合决策矩阵的构成原理进行了深入探讨,并由此构造了地下水位控制模型与土地灌溉系统的灰色决策模型,为流域地下水位的控制提供了一种新的研究方法。  相似文献   

Integrated management approaches for pink bollworm in the southwestern United States     

Thomas J. Henneberry  Steven E. Naranjo 《Integrated Pest Management Reviews》1998,3(1):31-52

The pink bollworm (PBW), Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae), is the key pest in cotton (Gossypium spp.) production areas in the southwestern United States and in many other cotton-producing areas of the world. The high costs of chemical control, continuing economic losses, secondary pest problems and environmental considerations suggest the need for ecologically oriented PBW management strategies. Extensive research has resulted in a broad array of monitoring, biological control, cultural, behavioural, genetic and host plant resistance methods that can serve as a base for the formulation of integrated PBW management systems. The life history characteristics of the PBW, in particular the high mobility of adults, indicate the need for combinations of selected integrated pest management (IPM) components implemented over large geographical areas. The areas involved present a wide range of PBW population densities, differences in cotton production methods and social and environmental considerations. The best option is tailor-made systems for targeted management areas with the selection of IPM components based on the PBW population density, crop production methods and economic feasibility. The unlikelihood of eradication indicates the need for long-term monitoring and programme maintenance following successful area-wide management. The success of area-wide PBW management is highly dependent on participation in the planning, site selection, implementation and assessment phases of the programme by all segments of the agricultural community. A highly effective extension--education communication programme is an essential component. Local uncoordinated efforts have not reduced the economic status of this pest in any area where it is an established pest. The potential long-term benefits of PBW population suppression on an area-wide basis appear to justify area-wide efforts in terms of reduced costs, more effective control, less environmental contamination and other peripheral problems associated with conventional control approaches.  相似文献   

乙脑病毒PrME基因在杆状病毒表达系统中的表达   总被引：2，自引：0，他引：2  

刘金华  高福 《畜牧兽医学报》1998,29(6):546-552

本试验将乙型脑炎病毒（ＪＥＶ）的ＰｒＭ／Ｅ基因的ＨｉｎｄⅢ－ＢｇｌⅡ片段（２．１ｋｂ）插入到杆状病毒载体ｐＡｃＵＷ３１的ＢａｍＨＩ位点,使外源基因置于多角体蛋白启动予下游,构建成转移载体ｐＡｃＵＷ３１ＪＥ,以Ｌｉｐｏｆｅｃｔｉｎ作为共转染试剂,将纯化的ｐＡｃＵＷ３１ＪＥ与Ｂｓｕ３６Ｉ线性化的杆状病毒ＡｃＭＮＰＶ．ＬａｃＺＤＮＡ共转染昆虫ｓｆ９经病毒蚀斑纯化技术和Ｘ－ｇａｌ与中性红双重染色技术,随机  相似文献   

论野火的三属性     

周道玮  岳秀泉 《草业科学》1998,15(6):64-67

野火泛指发生于野外植被中的火、归纳发现有３个基本属性,自然性,灾害性和工具性,对这３个属性进行明确的定义和认识,有助于理解野火的意义,为研究和生产奠定科学系统的理论基础。自然属性一是指其自然存在、二是指其对自然界有影响,三是指其他受其他自然因子制约。灾是自然界不可控事件造成的超越一定程度界线的损失。灾害属性即经济属性。每一次火都造成巨大的经济损失,包括林资源和草资源预防和扑救开始。工具是指可以拿来  相似文献   

用发酵罐制备嗜水气单胞菌疫苗用菌液培养条件的优化   总被引：5，自引：0，他引：5  

范红结  陈怀青  陆承平 《中国兽药杂志》1998,32(2):11-13

本试验探讨了用发酵罐培养嗜水气单胞菌灭活疫苗生产菌株Ｊ－１株菌液的最佳条件。分别以发酵罐和摇床在不同的培养条件下培养Ｊ－１株制备菌液,前者１２个批次,后者６个批次。比较不同的培养条件对细菌菌体数量及ＨＥＣ毒素产量的影响。结果表明：发酵罐培养优于摇床培养,以产毒素培养基于２８℃发酵罐通气培养Ｊ－１株,培养２８小时效果最佳,培养菌液含菌量达２．９×１０１０ｃｆｕ／ｍｌ,培养液上清的溶血价达２７,发酵液中残糖为０．１２ｇ／Ｌ,符合发酵工艺要求。  相似文献   

奶牛生产管理决策支持系统设计   总被引：1，自引：0，他引：1  

贾永全  苗树君 《家畜生态》1998,19(1):33-36

本文主要探讨黑龙江垦区奶牛生产管理决策支持系统（ＣＰＭＤＳＳ）的设计思想和构建方法,介绍了ＣＰＭＤＳＳ数据库、模型库、方法库及人一机交互系统的功能特点和实现途径,为ＣＰＭＤＳＳ的实施开发打下基础。  相似文献