共查询到20条相似文献,搜索用时 394 毫秒
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调查研究结果认为泡桐属叶毛类型有单枝毛、腺毛、叉状毛和树状毛4大类型.各类又有长柄、短柄或无柄之别.叶背有无叶毛和叶毛类型的不同对丛枝病的抗性有很大差异.叶背无毛或毛非常稀少对丛枝病高度感染,叶背毛为无柄(或几无柄)树状毛、短柄叉状毛和短柄、腺细胞小并无粘性腺毛的泡桐感病,叶背为不同类型的混合毛亦感病,但感病程度随长柄和短柄毛的比例不同而有所差异.叶背毛为较稠密的长柄树状毛、长柄叉状毛、长柄单枝毛和长柄、腺细胞大的粘性腺毛的泡桐为高度抗病.抗病的原因是抗传毒介体昆虫. 相似文献
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泡桐丛枝病是影响泡桐生长的一种主要病害,种源试验表明在毛泡桐种源中,除甘肃平凉未见发病以外,其它种源均有病害发生。江苏南京、湖北十堰、黄冈、陕西商县和辽宁大连5个种源发病较重,病情指数超过30%;白花泡桐丛枝病发病率较低,自然分布区南部的种源很少见到丛枝病发生,分布区北部与毛泡桐分布区有重叠的种源,丛枝病发病相对较重。毛泡桐起源靠西的种源发病较轻,随着经度的增加,丛枝病发病有增大趋势;白花泡桐发病与种源经度无关,而与纬度相关明显,呈现出纬度越高,发病率越低,病情指数越小的趋势。泡桐品种间丛枝病发病率和病情指数差异明显,通过品种选择可以获得抗病优良品种。 相似文献
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The effects of water stress and defoliation by Lymantria dispar on the successful infection of the fungal pathogen Biscogniauxia mediterranea in seedlings of the Turkey oak (Quercus cerris) were studied under controlled conditions. Seedlings were inoculated by spraying with a spore suspension of Biscogniauxia mediterranea and were subjected to different levels of water stress, insect defoliation, and combinations of the two factors. The leaf water potential was periodically assessed throughout the experiment. The fungus was isolated exclusively from seedlings deprived of water, and insect defoliation increased significantly the proportion of fungus isolation when the water stress was moderate. Thus insect defoliation seems to promote fungal colonization in case of moderate water stress. 相似文献
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经过2 a用3种病毒野外接种褐顶毒蛾Lymantria apicebrunnea幼虫试验,表明不同病毒接种褐顶毒蛾的感病死亡率差异极显著,文山松毛虫CPV对褐顶毒蛾效果较好,20 d野外接种感染死亡率为78%;云南松毛虫NPV次之,20 d野外接种感染死亡率为56.5%;从美国引进的舞毒蛾NPV对褐顶毒蛾没有明显作用。经室内检测,接种CPV和NPV的褐顶毒蛾感病死虫单虫病毒多角体含量较高,分别为1.77亿PIB/头和0.97亿PIB/头;褐顶毒蛾感染松毛虫CPV和松毛虫NPV死亡虫pH值分别为7.556和7.554。 相似文献
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The entomopathogenic nematodeHeterorhabditis bacteriophora Pionar (HP 88) and the bacteriumBacillus thuringiensis Berliner var.kurstaki were tested in the laboratory against the black cutworm, a widely distributed polyphagous insect pest of vegetables and field
crops. The experiment was conducted under 15.7 °C (14 to 19 °C) to simulate the average winter temperature in Egypt. The two
biocontrol agents influencedAgrotis ipsilon differently whereH. bacteriophora had a more promising control levels than that ofB. thuringiensis. Generally, nematode concentration of ca 500 infective juveniles/insect vial was highly effective (100% mortality) within
nine days post nematode infection. The highest concentration of the bacteriumB. thuringiensis var.kurstaki (2,000 Intern. Units/mg) gave significant larval control after 12 days of bacterial infection. Combined effect of both the
nematodes and the bacteria did not result in significantly greater control than that achieved by the nematodes used alone.
The present results indicated that nematodes could be used successfully against the black cutworm,Agrotis ipsilon larvae during the winter which is the active season of this insect pest in Egypt. 相似文献
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Shuhan Wang Bingbing Zeng Mohammed Abdelmanan Hassan Shuai Qu 《Journal of Sustainable Forestry》2013,32(5):369-384
ABSTRACTLarch defoliation by Harig (Pristiphora laricis) has caused great damage in China. In this study, an attempt is made to analyze the relationships between Harig infestation and various habitat factors via the analysis of representative needles and other environmental metrics that were collected from Saihanba Mechanical Forestry Farm of Hebei Province between 2007 and 2010. The population density per tree (PD), the percentage of insect-infected trees in one sample plot (PIIT), and the infected area (IA) are treated as dependent variables when analyzing the degree of infection. The study concludes: PD and PIIT differ significantly between areas with varying species composition; canopy density and stand density negatively correlate with PD; Harig appears not to infect young growth; and infections have the tendency to spread to high altitudes. In order to provide a basis for macro prevention and control of insect attack, the habitat factors most closely related to the occurrence of insect attack are inputted into an information load GIS model to estimate the potential damage from infection. 相似文献
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本文系统地综述了作者对杨尺蠖核型多角体病毒AciNPV进行理化特性研究和将其应用于AciNPV杀虫剂研制中的结果。通过对AciNPV进行分离提纯,血清学特性,蛋白质结构组成和病毒基因组研究,获得了大量的理化特性详细资料。文中还就昆虫病毒的同源性关系,感染病毒后的早期检测,以及对在我国发展昆虫病毒杀虫剂需要解决的问题,提出了理论依据和实用有效的检测技术等。 相似文献
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