Cause Botyosphaeria dothidea (asexual Fusicoccum aesculi) , a fungus, is associated with declining madrones. Drought stress is considered a factor encouraging disease development, as is heavy flowering and berry production.
Symptoms Branches dieback such that limbs and twigs appear burned. Tiny black pycnidia can be seen both on twigs and leaves. Symptoms progress from branch tips downward into the rest of the tree. Symptoms are similar to that caused by other pathogens such as Phytophthora ramorum.
- Prune out and destroy dead branches.
- Although madrone is drought tolerant, consider infrequent deep watering during extended drought periods. Do not focus waterings near the trunk.
Reference Bennett, M. and Shaw, D. 2008. Diseases and insect pests of Pacific madrone. OSU Extension Service EC 1619-E.