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近年来,龙眼腐烂病(病原菌待查)时有发生。该病多发生在贴近表土的根颈处。病原菌侵染后,表皮出现不规则的褐色病斑,但病健交界不明显。在高温高湿环境中,褐变病斑出现水渍状棕褐色液体,皮层变软、变松、腐烂。腐烂病斑上下左右蔓延扩散,病斑上部树皮出现纵裂并流胶。当根颈皮层腐烂时,刨开表土,病斑下部的根系有时也呈腐烂症状。病情严重时,根颈部和根部的木质部都变黑褐色。然而部分病树的树皮无明显的腐烂症状,但树皮与木质部分离,形成层坏死,已呈黑褐色。病原菌侵染根颈皮层,树势开始衰退,病斑对应枝干叶片先褪绿,变黄,叶缘焦枯,叶片
In recent years, longan rot (pathogen to be investigated) have occurred. The disease occurred in close to the top of the root neck. Pathogen infection, the epidermis irregular brown spot, but disease is not obvious junction. In the high temperature and humidity environment, brown spots appear water stains brown liquid, cortex becomes soft, loose, decay. Spread up and down spread around the proliferation of lesions, the upper bark lesions appear longitudinal splits and gel. When the root neck cortex decay, dig the topsoil, the lower part of the lesion root sometimes decay symptoms. When the condition is serious, the xylem in the neck and root of the root becomes dark brown. However, some bark tree bark no obvious decay symptoms, but the bark and xylem separation, the formation of necrosis, has been dark brown. Pathogen infection of the root cortex, tree potential began to decline, the lesion corresponds to the first branch leaves greenish, yellow, leaf margin scorch, leaves