Black-Stain Root Disease
Leptographium wageneri
4 host plants · Fungal
Last updated
This profile contains verified disease data from extension databases. Regional field notes and expert review are in progress.
Roots show black wood discoloration with eventual decline. This disease spreads by root contact. Remove infected trees. The pathogen (Leptographium wageneri) favors moist conditions and enters through wounds or natural openings. You are most likely to see symptoms during the growing season when conditions shift between wet and warm. On susceptible hosts, the damage can progress quickly if left unchecked.
Favor resistant species. Plant at wide spacing to avoid pre-commercial thinning. Remove infected material promptly and improve growing conditions to limit pathogen spread. Good sanitation, adequate spacing, and proper irrigation practices reduce disease pressure over time.
Quick Reference
Management
Year-round; trees stressed by drought especially susceptible.
Fungal spores/mycelium transmitted by root contact or wood-feeding insects; infection through wounded roots.
Cultural Controls
- Favor resistant species.
- Plant at wide spacing to avoid pre-commercial thinning.
- Pre-commercial thinning is best done in the summer between June 1 and September 1 when bark beetles are not flying.
- Prevent tree wounding, soil disturbance, or other activities that decrease tree vigor.
- Reference Shaw, D.C., Oester, P.T. and Filip, G.M. 2009.
- Managing Insects and Diseases in Oregon Conifers.