柠檬桉流胶病的初步研究

A PRELIMINARY STUDY ON GUMMOSIS OF EUCALYPTUS CITRIODOR

柠檬桉流胶病初期病斑红褐色。内皮层腐烂呈黄褐色,边缘开裂。病斑深达木质部后,胶液从裂缝或病斑脱落处流出。惟病植株叶黄枝枯,生长逐渐衰退至死。从20余株病树上取病斑60个,逐个分离,经接种、再分离证明病原是Cytospora eucalypti 和 Macrophoma eucalypti 两种,主要是 Cytospora eucalypti。两种病菌均以菌丝体、分生孢子器在病树的病皮中越冬,雨水传播、伤口侵入。在林中活立木上接种,气温25℃时,Cytospora eucalypti 潜育期为21～28天,Macrophoma eucalypti 的为14～21天。用内吸杀菌剂治疗病斑效果好,保护树皮免受损伤是预防该病的根本途径。

First symptom of gummosis of Eucalyptus citriodor is producing red-brown canker on the bark,and eudodermis become yellow-brown.Some gum seep from woody-part under the necrosis bark.The leaves of diseased trees become yellow,even branches or whole tree may be killed.The sixty cankers from more twenty infected trees were isolated,inoculated to healthy trees and retrocultured.Gummcsis of Eucalyptus cicriodor was shown to be caused by cytospora eucalypti and Macrophoma eucalypti.Two fungi are resting - winter with mycelium and pyenidiums in the infected barks,they are transmited through rain and penetrated through wound.At 25℃,inoculations to the healthy trees, the incubation period of cytospora eucalypti is 21—28 days,for Macrophoma eucalypti it is 14—21 days,The effective methods for control are using fungicides to treat cankers and protect barks against the wound。