共查询到20条相似文献,搜索用时 171 毫秒
1.
2.
<正> 油茶紫斑病(Cercosporella sp.)是广西近年在病虫害普查中在普通油茶(Camellia oleifenaAbel)上新发现的一种叶部病害,分布于富川、贺县、蒙山、昭平、防城、柳州、柳江、三江、百色、浦北、岑溪等地,危害程度轻至中等。紫斑病主要危害油茶嫩叶。发病初期叶面病斑呈红色或暗红色小圆点,平或稍突起;后变为紫红色,圆形,边缘一圈的颜色较深,略比健部突起,中央部凹陷,背面平坦或稍隆起。病斑大小为0.5—3毫米,定形后一般不再扩展。发病后期病斑边缘一圈呈紫红色,中央部呈暗灰色或暗褐色,多数有圆形小黑点。黑色小点表面开裂后,露出分生孢子梗及孢子,成为霉点。最后病斑坏死,形成穿孔。一叶片可有病斑一至数块,有的多达几十块,布满全 相似文献
3.
桉树幼苗干叶溃疡,是桉树苗期常见的主要病害,为害蓝桉、直干桉幼苗,造成苗木叶、干枯死,严重时整床死亡。幼苗染病后,叶背、干部产生灰色病斑,苗木梢部萎蔫,病斑扩大,产生灰色溃疡,干部枯死,出现灰色刚毛状物和黑色,叶背也有黑点出现。刚毛状物是灰葡萄孢;黑点是冬毛孢。 相似文献
5.
兰花软腐病是严重危害兰花新芽和叶片的细菌病害.最令养兰者头疼,能使全叶变褐.发病严重时.整株枯死.现将其症状及防治方法介绍如下:症状识别。兰花软腐病是主要危害叶片的细菌病害,叶片发病时,开始出现水渍状圆形或椭圆形污白色小斑点。在1—2天内.病斑迅速扩大,变成褐色斑.这时叶表面失去光泽,并略具皱纹,病部组织稍凹陷。 相似文献
6.
梨树主要病虫害及防治 总被引:1,自引:0,他引:1
梨树病虫害比较普遍,危害严重的主要有以下几种. 一、梨黑星病危害果实、叶片和新梢等.果实发病初生淡黄色圆形斑点,逐渐扩大的病部稍凹陷,上下生黑霉,后病斑木栓化、坚硬、凹陷并龟裂.叶片、新梢受害后,病斑呈疮痂状,周缘开裂. 相似文献
7.
绿亨6号防治枣树缩果病效果好 总被引:1,自引:0,他引:1
枣树缩果病(烂果病),属细菌性病害,又称束腰病,烧茄子病,是泊头市枣区果实的重要病害。受害症状为初期果皮上出现浅黄色晕黄病斑,环内略凹陷,后期果实表皮皱缩凹陷,颜色发暗。质地松软,果肉土黄,在成熟前造成大量落果,严重影响了枣果品质,给果农们造成了很大损失。 相似文献
8.
正西瓜的整个培育过程中,常出现多种病害,严重影响西瓜的正常生长和产量的提高。其中最为常见的有猝倒病、蔓枯病、疫病、炭疽病四大病害。猝倒病此病是西瓜苗期的主要病害。苗期根颈部呈水浸状病斑,而后病部变褐,幼苗近地面处明显缢缩而倒伏。土壤温度低、温度大时有利菌的生长与繁殖,所以 相似文献
9.
湿地松针叶病害与土壤养分条件的关系研究 总被引:1,自引:0,他引:1
通过野外调查和室内鉴定分析23决标准地基础数据,采用Fisher准则下的多元线性判别函数的计算方法,对湿地松植株感病指数与土壤属性因子进行判别分析和相关分析,并对其结果进行探讨论证。通过施肥效应试验检验,结果表明:湿地松叶部病害(主要是褐斑病和赤枯病)与土壤养分条件的多无线性判别函数公式可以预测湿地松是否感病及感病程度,R值越大,感病越轻;湿地松叶部病害的关键土壤因子是K%含量及全N/全K比值大小,病害感病指数与全K%含量呈负相关,与全N/全K比值呈正相关;施用钾肥对抑制病菌生长发育、减轻病害有一定效果,而施用氮肥过多,会导致病害加剧。 相似文献
10.
11.
T. R. Gordon S. C. Kirkpatrick B. J. Aegerter A. J. Fisher A. J. Storer D. L. Wood 《Forest Pathology》2011,41(3):227-232
Pitch canker, caused by Gibberella circinata, was discovered in California in 1986. Although initially quite damaging to Monterey pines (Pinus radiata), the severity of pitch canker has moderated in areas where the disease was first observed and some trees appear to have recovered completely. The absence of symptoms on trees that were once severely affected implies they have become more resistant to the disease. Experimental work has shown that P. radiata can manifest systemic induced resistance (SIR) in response to infection by the pitch canker pathogen and observations of disease remission may indicate that SIR is operative under natural conditions as well. As a test of this hypothesis, the susceptibility of trees in remission was assessed by inoculating them with G. circinata and recording the extent of lesion development. In addition, randomly selected trees in areas that differed in residence time of pitch canker were inoculated to determine if trees with a longer period of exposure to the pathogen were more resistant to the disease. The results of these tests showed that 89% of trees observed to be in remission sustained very limited lesion development, consistent with resistance to pitch canker. Furthermore, trees in areas where pitch canker was well established tended to be more resistant than trees in areas where the disease was of more recent occurrence. In sum, these findings support the view that SIR occurs in P. radiata and is contributing to a moderation of the impact of pitch canker under natural conditions. 相似文献
12.
Quaking aspen is damaged and killed by many pathogens but throughout most of its range Entoleuca mammata, the cause of Hypoxylon canker is the most serious. Hypoxylon canker has been the subject of study for over 85 years, yet gaps in our understanding of this disease remain and practical control measures for existing stands are lacking. Numerous interacting host and pathogen factors have complicated investigations and have resulted in conflicting results among researchers. This synthesis of the literature examines our knowledge of the genetics of the host and pathogen and the biology of the disease. Regenerating dense stands and selecting superior, disease resistant clones with pre-infection resistance mechanisms based on long-term field trials are strategies most likely to be effective in minimizing losses caused by this disease. 相似文献
13.
14.
15.
Qian Wang Yuanze Shi Junnan Yu Lulu Shan Deying Sun Shuqing Yang Xiaofei Chen 《Forest Pathology》2023,53(3):e12815
Styphnolobium japonicum (L.) Schott is a deciduous tree belonging to family Fabaceae and has been widely planted as garden greenery in China. In May 2021, a serious branch canker disease was observed in Alaer City. In order to identify the pathogen, five fungi were isolated from the diseased branches and the pathogenicity was evaluated by inoculating the branches outdoors. The pathogen was re-isolated from all the inoculated branches, therefore fulfilling Koch's postulates. Based on the morphological characteristic and polygenetic analysis using the internal transcribed spacer region, β-tubulin and the translation elongation factor 1-alpha, the pathogen was identified as Fusarium solani. This is the first report of F. solani as the causal agent of a branch canker of S. japonicum in Xinjiang of China. 相似文献
16.
17.
18.
19.
Several Aegean (Greece) and Anatolian (Turkey) cypress provenances were studied for resistance variability to bark canker, a disease caused by the fungal pathogen Seiridium cardinale. The investigation also examined whether the low disease rate within the natural area of cypress was due to genetic or geographic‐climatic reasons. Results demonstrated strong variability for the ‘bark canker resistance’ character, in particular for trees within families. As trees from the provenances studied were not found to have genetic superiority for bark canker resistance, the above‐mentioned low disease rate could be due to geographic‐climatic barriers that inhibit the development of the fungus or its ability to infect the host. Several half‐sib progenies exhibited high resistance, suggesting that this character is totally inherited through the maternal line. Should this finding be confirmed by further research, it would facilitate the task of genetic improvement for resistance, allowing progenies of resistant trees to be obtained. 相似文献