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核桃常见病害的识别与防治 总被引：1，自引：0，他引：1
一、枝枯病。真菌病害,主要危害枝干,造成枯枝和枯干,严重时可造成大量枝条枯死,对产量影响较大。病害先从幼嫩短枝开始发生,然后向下蔓延直至主干。受害枝条皮层初呈暗灰色,后变浅红褐色,最后变成深灰色,并形成很多黑色小粒点（即病菌的分生孢子盘）。病枝上的叶片逐渐变黄、脱落,枝条枯死。湿度大时,病部长出大量黑色短柱状物（即分生孢子）。病菌以菌丝体和分生孢子盘在病部越冬,翌春条件适宜时产生分生孢子,借风雨、昆虫等传播。 相似文献
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一、柿树角斑病危害叶片及果蒂.初期在叶面出现黄绿色不规则病斑.随病斑扩展颜色加深,呈浅褐色.后期受叶脉限制,病斑呈多角形,中间黑褐色,边缘黑色,其上散生许多黑色小点,为病菌的分生孢子堆.病斑往往连接在一起,形成大型枯斑.果蒂上的病斑近圆形,深褐色,病斑上生黑色小点粒.叶片早落,造成枝条发育不充分,容易遭受冻害而枯死,或引起其他病害. 相似文献
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撑×绿杂交竹梢枯病病原及发生规律研究 总被引：4，自引：0，他引：4
通过分离、接种、再分离首次证实杂交竹梢枯病的病原为暗孢节菱孢菌Arthrinium phaeospermum(Corda)M.B.Ellis.该病菌以菌丝体和子实体在病组织、病组织残体或土壤中越冬,其中病组织中菌丝体和子实体中的分生孢子为越冬的重要形式,是痛害发生主要的初侵染源;病菌主要以分生孢子或菌丝通过伤口从节叉处侵入;病原菌主要通过孢子借助风力和雨水传播,从4月初开始释放孢子,6月为病原孢子释放的高峰期,并以分生孢子进行再侵染. 相似文献
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梨黑斑、黑星病的防治 总被引：1，自引：0，他引：1
黑斑病是由半知菌引起的病害。病原物以分生孢子及菌丝体在病枝梢、病芽、病果上越冬 ,次年从病组织上产生新的分生孢子 ,靠风雨传播。当孢子萌发后 ,通过梨树皮孔、气孔侵入或直接穿透寄主表皮侵入 ,引起初次侵染。然后在梨树整个生育期可多次产生新孢子进行侵染危害 ,形成重复侵染。1 病 状梨黑斑病主要危害叶、果实、新梢。嫩叶最易受害 ,初期出现针头大小圆形黑色斑点 ,随后逐渐扩大成圆形或不规则直径为 1cm左右的病斑 ,病斑中心呈灰白色 ,边缘黑褐色 ,病斑多时可相互结合成凹陷的不规则大斑 ,在潮湿的条件下病斑表面形成黑霉物 ,… 相似文献
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1危害症状
葡萄毛毡病由瘿螨寄生所致，主要危害叶片，严重时也危害嫩梢、幼果、卷须及花梗。叶片受害初期，叶背面产生许多不规则的白色病斑，扩大后叶表面隆起呈泡状，叶背面凹陷处密生一层毛毡状灰白色绒毛，后期斑块逐渐变成褐色，严重时叶片皱缩、变硬、干枯脱落。 相似文献
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葡萄毛毡病的发生与防治 总被引：1，自引：0，他引：1
一、危害症状
葡萄毛毡病由瘿螨寄生所致,主要危害叶片,严重时也危害嫩梢、幼果、卷须及花梗。叶片受害初期,叶背面产生许多不规则的白色病斑,扩大后叶表面隆起呈泡状,叶背面凹陷处密生一层毛毡状灰白色绒毛,后期斑块逐渐变成褐色,严重时叶片皱缩、变硬、干枯脱落。 相似文献
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The species composition of the endophytic mycobiota in leaves of Japanese beech trees (Fagus crenata) and the sources for leaf infections were studied in a forest reserve situated in central eastern Honshu, Japan. To clarify the mechanism of infection of leaves, half of the branches were covered with polyethylene bags and species composition and levels of endophytic fungal infection were then compared with those of unbagged controls. Isolations were carried out from the leaves, petioles, and current‐year twigs of both, bagged and unbagged branches. Additionally, species composition was detected in overwintered terminal buds of beech trees and in the leaves of potted seedlings that had been placed in the field in different seasons. The species assemblage of the unbagged leaves, petioles, and current‐year twigs was dominated by Mycosphaerella buna, Ascochyta fagi, Periconiella sp., and Tritirachium sp. Other frequently recovered species were Xylaria sp., Phomopsis sp., and Tubakia dryina. Mycosphaerella buna and A. fagi were never isolated from leaves on bagged branches. A. fagi was, however, detected on both bagged and unbagged petioles and current‐year twigs at comparatively low isolation frequencies. The detection of Periconiella sp. on all occasions in both bagged and unbagged leaves was a characteristic feature that differs from those of the other three dominant endophytic fungi. The fungus was also detected without significant differences in bagged and unbagged petioles and current‐year twigs on most sampling dates. Furthermore, Periconiella sp. was isolated from immature twigs inside the bud scales. Tritirachium sp. was frequently detected in unbagged leaves and petioles and in both bagged and unbagged current‐year twigs, and rarely in bagged leaves and petioles, but was never recovered from terminal buds. The results of the potted seedling experiments revealed that all four dominant species had airborne inocula. The infection of leaves by M. buna occurs exclusively by airborne propagules, i.e. ascospores in spring and conidia in autumn. In Periconiella sp. hyphal growth of the fungus from immature twigs inside the buds into the leaf tissues was suggested in addition to infection by airborne inocula. Tritirachium sp. hyphae were suggested to grow from previous‐ to current‐year twigs. Ascochyta fagi was present in the outermost scales of overwintered terminal buds, but no systemic growth of the fungus into the petioles and current‐year twigs was observed. Our technique of covering the branches before new leaves unfolded was effective in preventing infection by airborne inocula of endophytic fungi. 相似文献
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通过多年大量室内和田间试验与调查,研究了金丝小枣浆烂病病原菌仁果囊孢壳菌Physalospora obtuse对金丝小枣各器官和枣果的侵染、孢子萌发、越冬寄主、子实体形成规律和侵染率与降水量关系.结果表明,病原菌于6月上旬侵染枣吊、果柄,7月上旬开始侵染枣果,8月下旬为侵染高峰期,9月中旬为田间发病高峰期,前期侵染呈潜伏侵染状态.金丝小枣树皮、枣头、枣股及落果、落叶、落吊均为病原菌越冬场所,其中以落果为主.枣园周围杨树、榆树、刺槐、苹果、梨树、桃树亦为病原菌越冬寄主并传播病原菌造成危害.病原菌在越冬病枣果上可形成有性和无性繁殖体;当年病枣果形成分生孢子发生再侵染.8月中旬、下旬雨量大,是造成金丝小枣浆烂病大发生的关键因子. 相似文献
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Comparison of two methods for evaluating infection of young poplar leaves by Marssonina brunnea . Two methods for evaluating foliar infection by Marssonina brunnea have been compared on 783 twigs. They appear to be correlated. Distribution in infection classes can be coded and this allows a prediction of the number of spots per square centimeter. Application of the code to two other experiments is discussed. 相似文献
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广东桐花树群落上的柑橘长卷蛾研究 总被引：1，自引：0，他引：1
柑橘长卷蛾是红树林桐花树群落的重要害虫,在广东省局部区域的红树林保护区,已经对桐花树造威严重危害、对秋茄造成危害。柑橘长卷蛾在桐花树1年完成6代,以中龄幼虫越冬,第1～5代虫历时38～58d,越冬代虫历时130～137d。在桐花树群落,幼虫危害嫩芽、叶片、花序和果实;在桐花树＋秋茄群落,幼虫危害秋茄的嫩芽和嫩叶片。在桐花树群落,5月上旬-5月下旬和9月上旬～10月上旬,受害嫩芽数量与受害叶片数量有两个高峰期,柑橘长卷蛾种群数量消长规律与受害嫩芽与受害叶片数量的变化规律成正相关,柑橘长卷蛾种群数量全年也对应有两个高峰期,但秋季害虫高峰期害虫的总数量只有春季暴发期害虫总数量的29％。柑橘长卷蛾数量与捕食性蜘蛛数量的比例为1：0．33,林间捕食性蜘蛛数量的比例偏低。 相似文献
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Young leaves are conventionally used in the analysis to study the nutrient status of evergreen plants and their responses to environmental changes, but the role of old leaves remains poorly understood. We selected two stand types in 31-year-old Chinese fir (Cunninghamia lanceolata) plantations with similar soil conditions but different stand densities, to test the hypothesis that nitrogen (N) concentration of old leaves and twigs is more sensitive to stand density than that of young ones. Leaves and twigs were sampled and sorted into young (one-year-old) and old (two- and three-year-old) groups. Significant differences in N concentration and carbon: nitrogen ratio between the low-density stand and high-density stand were only found in the old leaves and twigs but not in the young ones. Although the N resorption efficiency did not vary significantly with stand density, the annual N resorption rates were increased in old leaves and relatively young twigs at high stand density. These results show the potential use of old tissues in the nutrient analysis in Chinese fir plantations. Testing the generality of these results could improve the use of foliar analysis as an indicator of nutrient status and environmental changes in evergreen tree species. 相似文献
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朴平刺巢沫蝉ＨｉｎｄｏｌｏｉｄｅｓｓｐａｒｓｕｔａＪａｃｏｂｉ模式标本采自福建邵武，寄主不详。生物学尚无详细报道。作者在山西太谷小叶朴树ＣｅｌｔｉｓｓｉｎｅｎｓｉｓＰｅｒｓ．上发现其密度很大。１９９０—１９９２年研究结果表明：该虫寄主专一为小叶朴。一年发生一代，以老龄若虫在当年生枝上结钙质巢越冬。４月上旬，小叶朴发芽开花期，越冬若虫出蛰。成虫羽化期从４月中旬到５月。成虫雌雄比为１：１．０８。每雌虫平均产卵量为８０粒。卵产在小叶朴果实表面，成单列横排，一块有２－１４粒，以８—１０粒者为多，一果有１—４块；单粒卵为靴形。卵期约３０天，孵化率８２．８％。若虫共５龄，各龄历期分别为１８天、２０天、３０天、３０天、２３０天。６月和７月，幼龄若虫以排泄物在果柄上结夏巢，隐蔽巢内取食；８月份第３龄若虫退出夏巢，迁移到当年生枝上结冬巢。并在其中取食发育，越冬，直到翌年春末羽化为成虫。夏巢和冬巢均为螺旋形，蜗牛壳状，灰白色，质硬，化学成份主要为碳酸钙ＣａＣＯ３。但夏巢远小于冬巢。对各虫期形态特征作了描绘。 相似文献
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[目的]以花楸树为研究对象,探究不同部位物质成分组成和含量差异以及不同生境条件对物质含量的影响。[方法]采用有机溶剂浸提及液相色谱法测定了花楸树不同部位(嫩枝、嫩叶、成熟叶、鲜果和干果)营养和药用物质。[结果]结果表明:花楸树不同部位含有丰富的营养和药用物质,其中成熟叶片中维生素C、类胡萝卜素和黄酮类物质含量较高,干果中蛋白质、可溶性糖、总酚、花色苷和单宁含量较高;与北京花楸相比,花楸树不同部位蛋白质、花色苷、黄酮类物质和总酚含量均较高,其中果实中花色苷和类胡萝卜素含量分别约为北京花楸的3倍和5倍,成熟叶片中的黄酮类物质和总酚含量约为2倍;花楸树新鲜果实中黄酮类和酚类物质种类丰富,其中槲皮素和表儿茶素的含量最高,且分别约为北京花楸的1.5倍和3倍。[结论]与北京花楸相比,花楸树的营养物质和药用成分的含量更高,值得加强其果实和叶片中黄酮和果实酚类物质资源的开发利用。 相似文献
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普通油茶对炭疽病抗性的病理学研究张常青关键词普通油茶、油茶炭疽菌、抗病类型、孢子萌发与侵入由于油茶炭疽病菌（ＣｏｌｅｔｏｔｒｉｃｈｕｍｃａｍｅｌｉａｅＭａｓｓｅｅ）的危害，使普通油茶（ＣａｍｅｌｉａｏｌｅｉｆｅｌａＡｂｏｌ）大量落花落果，这是严重影响... 相似文献