Grapevine Trunk Disease
Eutypa lata, Botryosphaeria spp., Phaeomoniella chlamydospora, and Phaeoacrem...
2 host plants
Last updated
Grapevine trunks weaken and decline from internal fungal infection, often without obvious external signs until vines collapse. Multiple fungi cause different trunk diseases affecting vines. Prevent by using certified disease-free stock, making clean pruning cuts, and avoiding mechanical injury to trunk and cordons during management.
Prevention works better than treatment for grapevine trunk disease. Choose resistant varieties when they exist, site plants where air moves freely, and maintain good sanitation by removing debris and infected material. When chemical intervention is necessary, timing matters more than product: apply protectants before the infection window, not after symptoms appear.
Quick Reference
Management
Fresh pruning wounds, especially during wet weather (Nov-Mar in Puget Sound lowlands). Wounds made in early winter remain susceptible longer than late-winter wounds. Spore release requires rainfall; infection is negligible during dry periods.
Spores (ascospores) released after 2+ hours of rainfall; airborne dispersal to fresh pruning wounds. Infection occurs year-round in maritime climates but peaks Nov-Mar during pruning season. Wounds remain susceptible 2-4 weeks post-cut; susceptibility decreases via negative exponential model.
Cultural Controls
- Time pruning for dry weather windows (48hr minimum dry forecast)
- Prune late in dormancy (late Feb-Mar) for faster wound healing
- Double pruning: rough cut Dec/Jan, final cut late Feb/Mar
- Remove cankers: prune 4-6 inches below visible discoloration
- Burn or bag infected wood; do not compost
- Sterilize tools between vines (isopropyl alcohol or 10% bleach)