1病害症状疫霉病菌可侵染哈密瓜植株的根、茎、叶、果实。尤其以接近地表的根颈部、土壤表面下10~30cm处的主根和靠近瓜沟壁的侧根发病最重。发病初期,靠近地表面的根颈基部产生暗绿色、水浸状的病斑,病斑扩展迅速,几天后患病部位缢缩,变为灰褐色。由于根颈部组织受到破坏,造成地上部瓜 1 disease symptoms Phytophthora infestation Hami melon plant roots, stems, leaves, fruits. Especially near the surface of the root and neck, the root surface of the soil 10 ~ 30cm at the root and close to the melon ditch wall of the most serious side. Early onset, close to the surface of the base of the root of the neck produce dark green, flooded lesions, lesions expanded rapidly, a few days later the affected area constricted, turning gray-brown. As the root neck tissue is destroyed, resulting in the Ministry of melon