Interior Needle Blight
Multiple fungi (Rhizosphaera spp., Stigmina spp., Lirula spp., and others dep...
15 host plants
Last updated
This profile contains verified disease data from extension databases. Regional field notes and expert review are in progress.
Interior needles on noble fir yellow and brown before dropping, leaving only current-year growth. Multiple fungi cause this needle cast problem, especially in dense plantings with poor air movement. Provide adequate spacing, weed control, and canopy thinning. Trees look sparse but remain healthy; this is mainly cosmetic.
Remove blighted tissue promptly, cutting well below visible symptoms. Improve air circulation by thinning dense growth. Avoid overhead watering, especially during bloom and new growth periods when tissues are most susceptible. For recurring problems, preventive fungicide applications timed to protect new growth can reduce infection, but cultural controls should be your first approach.
Quick Reference
Management
Spring through early summer (BBCH 10-19). Current-year needles susceptible during rapid growth.
Prolonged wet weather; poor air circulation; dense plantings; shaded conditions; tree stress
Cultural Controls
- Provide proper culture.
- Healthy trees are more resistant to stress and disease.
- Clear weeds from around trees, and maintain good air circulation in plantings.
- This reduces many fungal infection, and may be useful.