Project title
Evaluating the adoption and efficacy of grapevine leafroll disease control in the South African wine industry
Project number
Pathsol HR 26-01
Project leader
Mr Herman Rossouw
Institution
Patho Solutions
Start date
2026
Project description / Aim and industry relevance
Grapevine leafroll disease (GLD) remains a significant constraint to productivity and wine quality in South Africa, causing substantial economic losses despite long-term investment in control measures. This project will evaluate the adoption, implementation, and effectiveness of current GLD control practices across the wine industry. Using industry surveys supported by field inspections, the study will assess how control strategies are applied in practice and model the economic benefits derived from damage offset by these measures.
The primary aim is to generate evidence-based insights into the effectiveness and economic value of existing GLD control strategies. The project seeks to quantify the extent to which current practices reduce yield and quality losses, estimate the financial benefits, and identify gaps or inefficiencies in disease management to inform improved decision-making.
GLD can reduce vineyard productivity by an estimated 30–50%, posing a serious threat to vineyard longevity, profitability, and sustainability. By providing the first comprehensive evaluation of GLD control efforts in South Africa, this project will support more efficient allocation of resources, refinement of disease management strategies, and improved return on investment for producers. The outcomes will contribute to enhanced vineyard sustainability, strengthened economic resilience, and the continued competitiveness of the South African wine industry in global markets.
This project has five objectives:
- Select participant producers.
- Survey participants regarding GLD control practices.
- Correlate GLD control measures with infection levels.
- Model the economics of GLD control.
- Compile findings.
The project has received support and positive feedback from industry organisations and wineries.