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Willow Watermark Disease



P_wllowwtrmkdis

Willow Watermark Disease

Usually appear in

Spring to Autumn.


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Caused By:-     The Bacteria Brenneria salicis

Description

This disease is caused by the Bacterium Brenneria salicis(formerly Erwinia salicis) and damages willow trees throughout the world. The disease is spreads rapidly in the wood vessels, which transport the water from the roots. In multiplying the bacteria secrete substances that that damages the vessels and create the watermark stain in the wood. It is known as watermark disease because the wood of infected trees has a dark watery stain. The crown of the tree tend to die back, as though caused by honey fungus, but it rarely kills the entire tree. One of the first signs that a tree has the disease is that the first spring leaves turn red and die with die-back of the branches. An ooze may be emitted by branches. This ooze contain the bacteria which can be spread by various animals.


Control

Very little can be done for infected trees apart from removal and burning as the bacteria spreads to most parts of the tree.



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