Witches' brooms are dense clusters of twigs or thickened stems that develop on the branches of woody
trees. Leaves and shoots may become distorted, dwarfed, and discolored. Witches' broom results from diseases such as powdery mildew or rusts, mistletoe, or from insect
and mite feeding. Herbicides also can cause witches' brooms to form.
Provide plants with proper cultural
control to keep plants vigorous. Prune out witches' brooms at least several inches below where they form.
broom symptoms on oak