Bacterial blight of grapevine

Bacterial blight of grapevine, caused by the pathogen Xylophilus ampelinus, is a destructive vascular disease affecting vineyards globally. The bacterium colonizes the xylem vessels, disrupting the translocation of water and essential nutrients, which eventually leads to the collapse and death of the vine.

The disease primarily impacts Vitis vinifera cultivars. It is considered a significant quarantine pest in many viticultural regions because infected nursery stock can easily spread the pathogen over long distances, leading to localized outbreaks that are difficult to eradicate.

Early symptoms appear in spring when buds fail to burst or produce weak, necrotic shoots. As the season progresses, leaves develop irregular brown spots with chlorotic haloes. Characteristic deep longitudinal cracks or fissures appear on the stems and arms, occasionally exhibiting bacterial ooze under humid conditions.

Environmental conditions such as cool, wet springs are highly favorable for the dispersal and infection of Xylophilus ampelinus. The pathogen survives in the woody tissues of infected vines and is disseminated via contaminated pruning tools, splashing rain, and systemic movement through propagation material.

Control strategies rely heavily on preventive measures rather than chemical eradication. Essential practices include planting certified virus-free and bacteria-free stock, rigorous sanitation of pruning equipment using appropriate disinfectants, and the prompt removal and destruction of symptomatic vine parts to reduce the inoculum pressure in the vineyard.