Witches' Broom Rust

Dense, bushy branch proliferation forms like a broom in the canopy, caused by rust fungi or pathogens infecting branches. Prune out brooms well below the affected area, or remove heavily infested trees.

Rust fungi often need two different host plants to complete their life cycle, so identifying and managing the alternate host can break the cycle. Remove heavily infected leaves and dispose of them away from the garden. Improve air circulation to speed leaf drying after rain. Fungicide applications are most effective as preventive treatments before symptoms appear; once pustules are visible, the current infection cycle is already underway.