Leafroll
Grapevine leafroll virus
38 host plants
Last updated
This profile synthesizes data from multiple published sources. Expert field review is in progress.
Leaves roll downward and become thick and brittle, a characteristic virus symptom most visible on new spring growth of infected plants. No cure exists for viral infection; remove infected plants entirely to prevent spread to nearby healthy stock. Use only certified virus-free planting material from reputable nurseries for all new plantings to prevent introduction.
Start with cultural controls: remove infected tissue, improve drainage and air circulation, and keep foliage dry when possible. Leafroll responds best to early intervention, so scout regularly during the growing season and act at the first sign of symptoms. Chemical controls exist for severe cases but work best as preventive treatments before infection takes hold.
Quick Reference
Management
Initial infection occurs when mealybugs and soft scales feed on infected vines and transmit to healthy vines during spring and early summer (April-July). Symptoms typically appear 1-2 growing seasons after infection. Foliar symptoms are most obvious in late summer and fall (August-October) as temperatures cool and veins/blade color becomes visible. Delayed fruit maturity and reduced sugar content are evident at harvest. Once infected, vines remain infected for life with progressive vigor decline. Source: UC Davis, WSU research
Symptom expression is cultivar-dependent and temperature-related. Red varieties show striking red to purple interveinal coloration in late summer when ambient temperatures drop. White varieties show chlorotic symptoms. Warm growing season temperatures (22-28°C) favor mealybug and soft scale activity and virus multiplication. Stressed vines (drought, poor soil) may show more severe symptoms. Cooler fall temperatures trigger visible color symptoms in susceptible cultivars. Source: UC Davis research