牡丹红斑病的研究

牡丹红斑病在山东菏泽牡丹栽培区的发病率达50％左右，病重的牡丹园可达90％以上。从8批次384个样品中分离获得512个分离株，经筛选、纯化、回接试验，依其培养性状和形态特征，病原菌鉴定为牡丹枝孢Cladosporium paeoniae Pass。病害发生与牡丹不同品种、初侵染源等因子密切相关。筛选出了50％多菌灵、70％甲基托布津等防治红斑病的有效药剂，应用800倍液从3月中旬牡丹展叶前至7月中旬防治4次，效果达90％以上，感病指数可控制在5以下。

Study on Red Spot Disease of Peony Tree

The red spot disease was one of the important diseases of peony tree and was widely spread in Heze peony tree cultural region in Shandong Province. The infecting rate was about 50% in most peony gardens, and 90% in seriously infected garden. 512 isolates were obtained from 384 samples of 8 batches, by screening, purifying and re-inoculating test, The pathogen was identified as Cladosporium paeoniae according to its cultural and morphological characteristics. The occurrence of disease was closely correlated to the initial infection sources and species of peony tree. Some fungicides, such as the 50% carbendazim, 70% thiophanate-methyl were proved to be effective to control the red spot disease. 800-fold of the fungicides had about 90% efficiencies when spreading for 4 times from middle March to middle July and the infection index could be controlled lower than 5.