Cryptovalsa

Cryptovalsa is a genus of fungi belonging to the Ascomycota phylum, known to cause diseases in woody plants, most notably grapevines. This pathogen is associated with wood-decaying processes and is considered part of the complex of fungi that lead to the slow decline and eventual death of perennial crops.

The fungus primarily targets the xylem and phloem tissues of the plant. Infection typically occurs through pruning wounds, frost cracks, or other mechanical injuries to the bark. Once inside, the fungus colonizes the wood, interfering with the transport of water and nutrients, which ultimately results in the weakening of the entire plant structure.

Symptoms of Cryptovalsa infection often present as dark, necrotic lesions in the wood, clearly visible when cutting through infected stems or trunks. Externally, the disease may cause stunting of shoots, chlorosis (yellowing) of leaves, and premature wilting of clusters. In later stages, small, black, pin-head-sized fruiting bodies (perithecia) appear on the surface of the affected bark.

The development of this disease is highly dependent on environmental conditions, particularly high humidity during the pruning season. Spores are easily disseminated by wind and water splashes. The economic impact is significant, as it leads to reduced yields, loss of plant vigor, and the necessity of removing entire infected vines or trees from the vineyard or orchard.

Managing Cryptovalsa requires a strict focus on preventive cultural practices, as chemical control of established deep-wood infections is limited:

• Perform pruning during dry weather to minimize the risk of infection.
• Disinfect all pruning tools with appropriate solutions between plants.
• Apply wound protection treatments, such as grafting wax or fungicides, immediately after major cuts.
• Systematically remove and burn diseased wood to reduce the inoculum load.
• Improve overall plant health through balanced fertilization and stress reduction.