|Image copyright: P. Goussard|
Esca is a grapevine disease believed to be caused by a complex of fungal pathogens. The aim of this project was to identify the Basidiomycete fungi associated with Esca disease in local vineyards and to study their biology.
The project was designed to achieve the following milestones:• Identification of fungi isolated from infected vines across different regions;
• Morphological classification of fungi associated with Esca;
• Taxonomic descriptions of new species;
• Pathogenicity trials;
• Spore trapping studies;
• Development of a PCR detection system.
- Internal and external symptoms associated with Esca have been characterised;
- The fungi associated with each symptom type have been identified;
- Spore trapping studies revealed that spores are released from fruiting bodies at large numbers from the end of May until the end of September which coincides with our traditional pruning periods. Susceptible wounds could therefore be prone to infection if not treated properly.
Significance of the study:This was the first in-depth study of the grapevine disease Esca in South Africa. Wood rot fungi can have a huge impact on production and can reduce the productive lifespan of grapevines significantly. Knowledge of the causal organisms and their infection pathways help to implement effective management strategies to control the disease.
Researchers: Francois Halleen & Lizel Mostert