- Witches' brooms, a clump of small weak branches arising from one point on a larger branch, form in infected trees
- Needles on brooms are pale green to yellow in summer
- Needles die and fall off in autumn, leaving a clump of bare branches in the winter
- Yellow to orange bumps form on needles within the witches' broom, and may release powdery orange fungal spores in summer
- The branch at the base of the broom may be unusually swollen or cracked
- Also infects chickweed, causing orange spots or blotches on leaves
- More information on Broom rust...