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一、引言1980年9月,在东京八王子朝川林业试验场水松苗上发现一种赤枯病.水松苗是从中国引进的,1978年栽植,在苗圃已2年生.在枯死的针叶和感病的绿枝上,观察到许多子实体,孢子堆呈暗绿色霉层,镜检是一种尾孢菌的分生孢子堆.其形态特征经研究证实与巨杉尾孢菌引起的柳杉赤枯病相似.二、症状针叶和绿枝梢上先产生小的淡红褐色斑点,病斑扩展到全针叶,即枯死脱落.绿枝上圆形病斑向四周扩展,当病斑环绕一周,即枝叶枯死.由于病情发展迅速,引起大量枝条枯死.苗木栽植两年,约有半数枯死.在叶落未枯死的枝茎上,不定芽可产生新叶.但新针叶会再次感病,逐渐枯死脱落.在枯萎的枝叶上,产生淡绿褐色到淡灰褐色的分生孢子堆.这些症状与巨杉尾孢菌引起的落羽杉赤枯病、墨西哥落羽杉赤枯病非常相似.
I. INTRODUCTION A red blight was found on the Korean pine seedlings at the Chaocho Forest Experimental Station in Hachioji, Tokyo, Japan, in September 1980. Shui pine seedlings were introduced from China, planted in 1978 and spent two years in nurseries. On the green branches of the disease, many fruiting bodies were observed, the dark green mold layer was found in the spore pile, and the microscopic examination was a conidiospore pile of cercospores. The morphological characteristics were confirmed by the study of Cryptomeria fortunei Second, the symptoms Symptoms of the needle and green shoots first produce a small reddish brown spots, lesion extended to the whole needle, that is dead off. Green branches on the circular lesions spread to the surrounding when the lesion around A week, that is, dead leaves. Due to the rapid development of the disease, causing a large number of dead branches. Seedlings planted two years, about half of the dead .In the leaves of the dead withered stems, adventitious buds can produce new leaves. On the withered branches and leaves, a pale greenish brown to pale gray brown coniferous pile was produced, and these symptoms were very similar to those of Taxodium distichum blight caused by Trichobacter sparus and the disease of Taxodium distichum in Mexico.