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近年来中国沙尘暴发生特点、成因及其防治对策 总被引：22，自引：5，他引：22
沙尘暴的发生是一个自然的过程 ,它的发生要具备三个条件 :强冷空气、气旋活动、地面干松的沙土。近年来强和特强的沙尘暴频繁发生 ,这与中国北方人类活动对地表覆盖的严重破坏 ,生态环境进一步恶化有关。不合理的人类活动增加了沙尘暴发生的机率 ,加剧了其危害程度。防治对策主要有 :增加地表覆盖 ,促进生态良化 ;加强沙尘暴多发区环境承载力的研究 ,促进区域资源、人口、环境的协调发展 ;建立沙尘暴预警系统与沙尘暴多发区环境质量动态监测预警系统 ;加强法制与管理力度 相似文献
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《植物检疫》1989,(5)
1987～1988年北京市四个地方发现三裂叶豚草 Ambrosia trifida L.,发生面积约42亩,鉴于豚草发生的趋势,北京市农业局1988年4月决定把豚草作为本市植物检疫对象补充名单。通过加强检疫,尤其是对调入本市的商品粮、种子和其他介体加强复检,以求 1987～1988年北京市四个地方发现三裂叶豚草 Ambrosia trifida L.,发生面积约42亩,鉴于豚草发生的趋势,北京市农业局1988年4月决定把豚草作为本市植物检疫对象补充名单。通过加强检疫,尤其是对调入本市的商品粮、种子和其他介体加强复检,以求阻止豚草在本市的扩大蔓延。1.普查北京市发生豚草的地点多在公路边、沟边、垃圾堆、个别果园,发生原因可能是随商品粮及其他物品输入而传入的。我站主动组织普查豚草的工作任务,1987年9月召开了现场会,请专家讲解了豚草 相似文献
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近年我国马铃薯病虫害发生特点与监控对策 总被引：5，自引：0，他引：5
马铃薯是我国重要的粮食、蔬菜和加工原料。近年来以马铃薯晚疫病为主的马铃薯病虫害发生日趋严重。本文系统总结了2008—2014年我国马铃薯病虫害的发生概况,分析其发生特点为病害重于虫害,地区间、年度间发生不平衡,马铃薯晚疫病重发频率高,土传病害、地下害虫呈加重趋势,以及新发病虫为害增多等。在马铃薯病虫害监测防控中存在着重视不够、技术规范缺乏、薯农防控意识不强等问题。提出了应进一步加强监测预警和技术研究、加强监测防控技术培训及新发病虫害研究等对策建议。 相似文献
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The nature of a reductive system which actively degrades mexacarbate in the rat intestine and liver was investigated. The system is characterized by its stability against heat and protease treatments and its requirements for a flavin cofactor and an acidic pH for a maximum activity. As a result of purification and spectroscopic identification attempts the system responsible for the above reductive activity was identified to be flavoprotein. Under anerobic conditions such flavoproteinflavin cofactor systems degrade mexacarbate first to 4-N-desmethylmexacarbate and then to polar water-soluble metabolites. 相似文献
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A whitefly (Bemisia argentifolii) resistance crisis climaxed in 1995 in Arizona cotton and prompted the development of an integrated resistance management strategy adapted from a program implemented in Israel in 1987. The strategy incorporated two new major elements: once-per-year use of the insect growth regulators (IGRs) pyriproxyfen and buprofezin, and measures to delay use of pyrethroids for as long into the growing season as possible. A three-stage chemical use recommendation was formulated comprising IGRs (Stage I), other non-pyrethroid insecticides (Stage II), and synergized pyrethroid insecticides (Stage III). Results from use of the strategy in the 1996 season were very promising. Insecticide use for control of whiteflies was reduced substantially. State-wide monitoring of whitefly susceptibility revealed significant reductions in resistance to synergized pyrethroids as well as increased susceptibility to amitraz. Susceptibility of Lygus bugs to key insecticides changed correspondingly with increases and decreases in whitefly resistance from 1994 through 1996. ©1997 SCI 相似文献
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A. D. Avgelis 《European journal of plant pathology / European Foundation for Plant Pathology》1986,92(4):147-152
Tomatoes grown in plastic houses in Crete have been inspected since 1980 for virus diseases. Plants with virus-like symptoms were checked by sap inoculation to test plants and the isolated viruses were identified by host reaction and serology. The most common viruses were, in order of frequency, tomato mosaic virus (ToMV), potato virus X, tomato bushy stunt virus (TBSV), potato virus Y and cucumber mosaic virus. The large use of ToMV-resistant cultivars reduces gradually the importance of ToMV while TBSV tends to become a serious problem of tomato in Crete.Samenvatting Van 1980–1984 werden op Kreta de in plasticfolie-kassen geteelde tomaten geïnventariseerd op de aanwezigheid van virussen. Verdachte plante werden door sapinoculatie op toetsplanten onderzocht. De daarbij geïsoleerde virussen werden daarna via de symptomen op de waardplanten en serologisch geïdentificeerd. In volgorde van belangrijkheid werden de volgende virussen het meest aangetroffen: tomatemozaïekvirus, aardappelvirus X, tomatedwerggroeivirus, aardappel Y virus en komkommermozaïekvirus, De laatste jaren is door de toenemende teelt van tomaterassen met resistentie tegen tomatemozaïekvirus het belang van dit virus sterk verminderd, terwijl het tomatedwerggroeivirus een steeds ernstiger probleem lijkt te worden. 相似文献
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利用祁连山老虎沟地区海拔4200m气象观测站2010年的观测资料,采用FAO Penman-Monteith公式,再利用作物系数法,对高寒草甸生长季(5月22-9月22)的蒸散发量进行估算和分析。结果发现:研究期共有124天,蒸散发总量为238.3mm,日均为1.87mm·d-1。生长初期、生长中期、生长末期的蒸散发总量依次为22.6mm,179.1mm,36.6mm,依次占研究期总量的8.4%,75.2%,15.3%。5月下旬至6月中旬,日均蒸散发量以较低水平缓慢上升;6月下旬迅速增加;6月末至7月中旬猛然回落;7月中旬至8月末,日均蒸散发量迅速上升且维持在较高水平;此后直到9月22日,缓慢减少。5-9月月蒸散发总量依次为6.6mm,46.4mm,74.5mm,77.6mm,33.1mm。 相似文献
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T. Kapari-Isaia A. Kyriakou L. Papayiannis D. Tsaltas S. Gregoriou I. Psaltis 《Plant pathology》2008,57(2):348-353
A new laboratory technique combining shoot-tip grafting in vitro and biological indexing on indicator plants was explored for the detection of citrus exocortis and related viroids. Τhree in vitro laboratory methods were used and compared with the classical biological method. With the classical in vivo method, diagnosis is based on the expression of symptoms on indicators 11–14 weeks after inoculation. In contrast, with the first in vitro method, microindexing in vitro of citron seedlings by graft inoculation, diagnosis was possible 12 days after inoculation; with the second method, microindexing in vitro of citron cuttings by graft inoculation, 20 days after inoculation; and with the third method, microindexing in vitro of citron cuttings by injection inoculation, 40 days after inoculation. Inoculated Etrog citron plantlets grown in vitro and tested by RT-PCR showed the same viroid content as the source plants. Of the three in vitro viroid indexing methods, microindexing on cuttings by grafting was easier and more reliable than microindexing either on seedlings or on cuttings by injection. 相似文献