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Witches Broom on Birch

Symptoms

Witches broom can be identified when twigs develop clustered together in the crown of the tree. They are said by people to look like a witch’s broom. These clusters of twigs in the tree can quite easily be confused with a bird’s nest, so when identifying the problem some care should be taken.

Cycle of infection

Witches broom is spread by water or air currents and also by mite infestation. The Birch could be infected at any time, most probably in mid summer when the mites are abundant in the warm weather.

Implications for host

The fungi itself is very slow to spread and can be pruned out with ease, but when witches broom takes effect it ruins the outline of the tree. This is not so noticeable in summer due to the leaves being out.

Treatments

To control this pest, it is best to prune out the growths. This will be an easy task if caught early enough, due to the fungi spreading slowly. There is no chemical product against this problem.

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