一苹果根头癌肿病的为害本病根据作者在果苗检疫及调查中,多发现在苹果苗木上的根茎部,侧根上有时也有发生,被害部生出小豆粒以至拳头大的瘤状物(如图),病部最初呈乳白色柔软海绵状,逐渐变为木质化,肿瘤的形状一般略带园形或各种畸形,肿瘤表面粗糙,往往长很多小砂粒似的小瘤。发生于地上部的,均为慢性,树不致立即枯死,但树体逐渐衰弱,树叶小,甚至于早期落叶,成树还表现出结果枯小,树龄缩短。 An apple root cancer disease damage The disease according to the author in the quarantine and investigation of fruit and seedlings, and more found in the roots and shoots of apple seedlings, lateral roots sometimes occur, the victimization of small beans and fist generation of large nodules (such as Figure), the Ministry of disease was initially milky white sponge-like, gradually become lignified, the tumor shape is generally slightly circular or a variety of deformities, tumor surface roughness, often grow a lot of small sand like nodules. Occurred above the ground, are chronic, the tree does not immediately dead, but the tree gradually weakened, small leaves, and even early deciduous trees also showed the results of small, shortening age.