Laminated Root Rot
Coniferiporia sulphurascens
9 host plants
Last updated
This profile synthesizes data from multiple published sources. Expert field review is in progress.
Western hemlock or Douglas-fir shows yellowing, reduced growth, and eventually topples. Coniferiporia sulphurascens causes laminated rot, visible as pages of rot separating at growth rings. The fungus spreads through root contact from stump to stump. Avoid building near infection centers; remove healthy trees adjacent to confirmed diseased ones to stop spread.
Avoid building near centers of root-rot infection. Construction activity usually worsens the situation and can lead to tree failures and property loss.
Quick Reference
Management
Root infection occurs year-round but active spread is Oct–May in cool, moist soil. Visible symptoms lag infection by 3–10+ years. Trees may show no symptoms for years while internal decay advances. Sudden collapse can occur when root system is sufficiently compromised. Replanted susceptible sites are at permanent risk. BBCH 10–89.
Root contact with infected wood and mycelium (primary spread mechanism). Infection most active in cool, moist soil conditions (Oct–May, optimal 40–60°F). Stressed, weakened trees are most susceptible. Poor drainage and waterlogged soils favor pathogen activity. Disease progression is slow.
Cultural Controls
- Avoid building near centers of root-rot infection.
- Construction activity usually worsens the situation and can lead to tree failures and property loss.
- Remove healthy appearing trees that are next to confirmed infected trees in the landscape, as these are likely to be infected as well.
- This will reduce root-to-root spread to other trees that are not yet infected.
- In mixed-species areas, favor resistant species such as cedar, pine, or hardwoods when planting, thinning, or harvesting.
- Excavating infected stumps has helped on industrial land.