泡桐腐烂病病原菌及发病规律研究

STUDY ON PATHOGENIC FUNGUS AND OCCURRENCE OF PAULOWNIA CANKER

泡桐腐烂病在山东、河南等省发生严重。病原菌为Valsapaulowniae Miyabe etHemmi,菌落生长最适温25℃,在0～3℃仍能生长。对碳源利用以麦芽糖及蔗糖为好,氮源以蛋白胨及牛肉膏为好。pH 范围2～4;菌落生长过程中分泌酸。分生孢子与子囊孢子在25℃、有丰富营养与空气及相对湿度100%条件下最易发芽;在0～5℃仍能发芽。以分生孢子出现机率大。伤口侵入,潜育期半月至4个多月,孢子全年可由风雨等传播,侵染期在9月至翌年4月,发病期为10月底至翌年4月下旬,孢子及菌丝在病斑内越冬。枝干有伤口是极重要的发病因素。

Paulownia canker occurs seriously in Shandong,Henan and other provinces.Thepathogenic fungus is Valsa paulowniae Miyabe et Hemmi.The optimum growth tempera-ture of colony is 25℃.however,it can grow at 0～3℃.Maltose and sucrose are the good nutriments as carbon source,while peptone and beef extract are the best nitrogen source.ThepH range for its growth is 2～4,The colony can secrcte acid in its growing process.Conidiaand ascospores germinate best at 25℃ and in the medium containing abundant nutriments.air and relative humidity 100%.However,it can germinate at temperature as low as 0～10℃.Conidia appear with more probability than ascospores in infection.Spores invadefrom wounds.The incubation period is half a month to four months and more.Spores maye spread by wind and rain perennially,but the infective stage is only from Sep.to Apr.ofthe following year.In the late of Oct.the disease begins to develop and stops developing inthe late of Apr.Spores and mycila over～winter in the lesion.Paulownia is easily diseaseddue to bad site conditions,improper management and weak growth potentials,The woundson the trunk are a very important factor in occunrence of paulownia canker.