杨树溃疡病潜伏侵染的研究

在陕西省杨树溃疡病(Dothiorella gregaria Sacc.)是一种严重的病害,分布普遍,危害130多个杨树品种、杂交种和无性系,其中有些树种如箭杆杨、北京杨、陕林2号杨、箭×钻杨等受害更为严重,常导致整株死亡,造成重大损失。据研究杨树溃疡病菌有潜伏侵染的特性,但在陕西省杨树苗木上未见其发病,有无潜伏侵染现象存在,更不清楚,为了弄清这一问题,我们于1987—1988年,对来自三个苗圃的24种杨树苗木

A STUDY ON THE LATENT INFECTION OF POPLAR CANKER

Poplar canker, mainly caused by Dothiorella gregaria Sacc., a pathogenic fungus, which may cause canker diseases on 132 species and cultivars of poplar tree, is a serious disease in Shanxi Province. Twenty-four species and cultivars of poplar seedings coming from three nurseries were applied to the artificial inducing test of latent infection of poplar canker. The results of the experiment showed that among six induced species of fungi (Dothiorella gregaria, Cytospora chrysosperma, Phoma sp., Fusicoccum sp., Pestalotiopsis sp., Sphaeropsis salicicola) D. gregaria possesed the highest latent infection rate. It was proved that the disease development was closely connected with the relative expanding degree of bark and that the most faverable condition for occurrence of the disease was that when the relative expanding degree of bark decreased to 66-68%.