西瓜花叶病是上海郊区常见的西瓜病害。1976年以来,危害面积逐年扩大,严重影响西瓜产量和品质。本病主要发生在春夏干旱时,多见于土壤板结根系发育不良的植株。患病西瓜根系先感病,然后叶面出现镶嵌斑驳症状,叶脉深绿向叶背卷曲,畸形新叶呈鸡爪状,叶簇生。植株矮化,节间缩短,根系生长差,根群小,根尖变褐。结出的西瓜果实小,表面凹凸不平,斑纹深浅不一;瓜瓤暗褐色,似烫熟,有腐败味,早发田块只瓜无收。取表现典型花叶病症的西瓜叶片,用浸 Watermelon mosaic disease is a common watermelon disease in the suburbs of Shanghai. Since 1976, the hazardous area has been expanding year by year, seriously affecting the yield and quality of watermelon. The disease occurs mainly in spring and summer drought, more common in the soil plate knot root well-developed plants. The diseased watermelon root is first susceptible to disease, then the mottled mosaic mottling symptom appears, and the dark green leaf veins curl. The deformed new leaf is in the shape of chicken claw and leaf clusters. Dwarf plants, internodes shortened, poor root growth, small root groups, root tip browning. Results of the watermelon fruit is small, uneven surface, different shades; Guabu dark brown, like boiled, corrupt taste, as early as the field only melon harvest confiscated. Take typical mosaic disease performance of watermelon leaves, with dip