Prunus Necrotic Ringspot
Prunus necrotic ringspot virus (PNRSV)
38 host plants
Last updated
This profile synthesizes data from multiple published sources. Expert field review is in progress.
Prunus necrotic ringspot causes ring-shaped lesions on fruit and leaves of stone fruit. This viral condition spreads through pollen and seed. Remove infected trees and replant with virus-tested stock. Control aphids and other vectors. Proper sanitation and resistant varieties offer the best management approach. Rot diseases are difficult to manage once established. Focus on prevention through proper culture and site selection.
Use nursery stock that has been tested and found to be free of all known viruses. If propagating your own trees, use both virus-indexed bud wood and virus-certified rootstock.
Quick Reference
Management
Newly grafted and budded nursery trees are highly vulnerable to infection and may show reduced bud-take. Young trees (1-5 years pre-bloom) can be infected by direct contact with infected pollen but symptom expression is minimal until tree maturity and flowering begin. Mature, flowering trees are continuously vulnerable to pollen-transmitted infection during bloom period. Hypersensitive rootstocks ('Krymsk 5', 'Krymsk 6') may show scion death even from latent infections.
Shock symptoms (sudden leaf deformations, chlorosis, necrosis) may develop shortly after infection, depending on climatic conditions. After shock symptoms, chronic symptoms develop including chlorotic rings, necrotic spots, and leaf deformity. Symptoms vary depending on virus strain, host species tolerance, and climatic conditions. Sweet cherry typically develops ring patterns and shot-hole appearance. Peach varieties show tatter leaf or ringspot symptoms. Cherry rugose mosaic strain causes leaf 'boating', turned-up leaf tips, and enations (rasp-like ridges). Cool spring weather often triggers more pronounced symptom expression.
Cultural Controls
- Use nursery stock that has been tested and found to be free of all known viruses. When propagating trees, use both virus-indexed budwood and virus-certified rootstock. Avoid propagating from infected trees. Establish new plantings in blocks, preferably away from older infected orchards to reduce pollen-mediated transmission. During bloom season, manage cross-pollination with virus-infected pollen sources nearby. Rogue infected trees from new plantings if few are affected early. Select tolerant rootstocks and avoid hypersensitive rootstocks like 'Krymsk 5' and 'Krymsk 6' if PNRSV is known to be present. Source: PNW Plant Disease Management Handbook; WSU HortSense