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61.
63.
P. van Dijk M. Verbeek I. Bos 《European journal of plant pathology / European Foundation for Plant Pathology》1991,97(6):381-399
While testing several samples of onion and of vegetatively propagated garlic, sand leek and shallot from a number of countries,
virus isolates with unusually flexuous particles were obtained by mite (Aceria tulipae) or sap transmissions. No aphid-borne poty-or carlavirus was transmitted by mites, and mite-borne virus isolates could not
be transmitted by aphids. The mite-borne isolates did not react with antisera to aphid-borne potyviruses ofAllium spp. or with the Agdia potyvirus group monoclonal. In contrast to the mite-borne onion and garlic mosaic viruses reported
in the literature, our mite-borne isolates induced no visible or only very mild symptoms inAllium spp., except isolates from shallot ‘Santé’ which caused diffuse striping. Heavily mite-infested test plants or plant samples
showed streaking and malformation due to mite feeding (tangle-top).
The mite-borne virus isolates could be classified with test plants and a discriminating antiserum into three groups, representing
two viruses and a strain of one of them. They are tentatively named onion mite-borne latent virus (OMbLV), garlic strain of
this virus (OMbLV-G), and shallot mite-borne latent virus (SMbLV). Mite transmission, length of virus particles (ca. 700 to
800 nm), and the presence of granular inclusion bodies in infected tissue indicate that the viruses belong to the mite-borne
genusRymovirus of the familyPotyviridae. OMbLV from shallot and onion, and OMbLV-G from garlic and sand leek, can be assayed onChenopodium murale but differ in their natural hosts. They are very common. SMbLV, to whichC. murale does not react, was isolated from shallot originating from Asia and Russia. 相似文献
64.
报道中国水螨属1新种刺突水螨Hydrachna tuberata sp.nov..其主要鉴别特征为:雄螨生殖域扁圆心形,雌螨生殖域桃形,均不长达EpⅣ的后中缘末端,p-Ⅱ背部具5根栓毛. 相似文献
65.
Wheat streak mosaic (WSM), caused by the Wheat streak mosaic virus (WSMV), which is transmitted by the wheat curl mite (Aceria tosichella), is the most prevalent virus disease of wheat in the Texas High Plains. Infected plants initially exhibit mosaic symptoms, which lead to severe stunting, complete chlorosis and, in the most severe cases, eventually plant death. Wheat plants infected with WSMV have lower forage and grain yields and exhibit reduced water-use efficiency compared to non-infected plants. The disease impact on water-use efficiency raises an important issue of whether diseased fields should be irrigated as frequently as non-diseased fields. The issue becomes more relevant when energy costs and the dwindling water resources from the Ogallala Aquifer are taken into consideration. This study examined the potential economic losses due to WSM, using data collected from two fields in 2007 and 2009. A hand-held hyperspectral radiometer was used to quantify severity of WSM in multiple 1 m2 plots along two transects, each stretching from the edges of the fields to their centers. Grain yield declined exponentially (R2 = 0.79, P < 0.0001) with increasing disease severity, as measured by reflectance at 555 nm. For economic analysis, grain yield from each plot was used for determining cost adjustments and linked revenues in relation to WSM severity levels, which allowed calculations of potential profit reduction. The method enables one to compare losses associated with different levels of WSM severity to a baseline with little or no WSMV infection. Results show that losses from the disease are primarily an outcome of reduced revenue due to a decrease in grain yield, and, as expected, losses incurred per unit land area rapidly increase with increasing disease incidence and severity. Furthermore, producers incur additional marginal losses when irrigating fields with WSM because there is little or no return for irrigation inputs, as water-use efficiency of severely diseased wheat is drastically reduced. Results from this study are useful in estimating losses at differing levels of disease incidence and severity and represent the first step in development of an economic threshold for wheat streak mosaic. 相似文献
66.
67.
柑桔锈螨是我国柑桔生产的重要害虫,在我国,一般每年有三个发生高峰期,造成对柑桔叶、果实的严重危害,在高温旱时危害尤为严重其发生适宜温度是23~32℃,最适温度是25℃,光周期是L:D=12:12,近年来已经对一些药剂如三氯杀螨醇产生了抗药性,就柑桔锈螨的发生规律、抗性和防治等进行了系统进行了叙述,并提出了综合防治措施。 相似文献
68.
Rostislav Zemek Miroslava Kurowská Ludmila Kameníková Gabriela Zemková Rovenská Jiří Havel František Reindl 《Journal of pest science》2005,78(2):115-116
Caraway (Carum carvi L.) belongs to the traditional crops which have been grown in Bohemia since the end of the 19th century. Depressaria daucella (Denis and Schiffermüller) and Aceria carvi Nal. are two main pests of caraway in the Czech Republic. The latter becomes a serious problem in major caraway-growing areas. So far, no effective method for its control is known. The aim of this paper is to describe the phenology of symptoms of A. carvi infestation and damage caused by this pest. Our observation revealed that although A. carvi overwinters hidden within leaves of young caraway plants, the first symptoms are usually not visible before the start of flowering. Though the initial density of the pest is low, the mite population multiplies during the season when the pest attacks plant tissues and causes development of galls on leaves and flowers. Comparison of healthy plants and plants infested by A. carvi showed that infested plants had significantly more umbels but produced far fewer seeds, and the yield of caraway was thus substantially decreased. Recommendations for crop management methods to suppress the pest are given.Electronic Supplementary Material Supplementary material is available for this article at 相似文献
69.
通过在曲阜孔林地区选择四种典型生境作为采集样点,定时定量采集土样,共分离获得标本8934号,经鉴定发现所采集标本隶属21科33属45种,其中含有16种中国新记录种。对鉴定出的45种甲螨进行区系分析表明,该地区土壤甲螨在世界动物地理区划中的分布,可以划分为8个区系型。在中国动物地理区划中可划分11种区系型。其群落分析表明:No-thrus asiaticus Aoki et ohnishi、Erembelba foliata Foliata hummer、Zygoribatula hailongensis、Ceratozetes japonicus Aoki、Scheloribates latipes为该地区的优势类群。多样性分析表明C样地多样性指数最高。 相似文献
70.
通过对无公害栽培苹果园山楂红蜘蛛发生分布规律及防治措施的研究发现,无公害栽培苹果园越冬态山楂红蜘蛛种群数量为平地园〉阳坡园〉阴坡园;越冬态山楂红蜘蛛在树体上集中分布在主干及第一层主枝的翘皮、环剥缝隙、剪锯口及气生根等处。从山楂红蜘蛛发生动态看,1a中有2次发生高峰,分别为3月底至4月初、6月底至7月初。早春彻底刮皮后,每株树上越冬态山楂红蜘蛛数量仅为未刮老翘皮树的3.77%;萌芽前喷5波美度石硫合剂防治越冬态山楂红蜘蛛,喷药7d后防效达90%以上;生长季应用1.8%阿维菌素3000倍液或24.5%绿维虫螨2000倍液控制山楂红蜘蛛危害的校正防效均在97%以上。 相似文献