Mastering the Mist: Combating Downy and Powdery Mildew with Innovation and Tradition

Grape Varieties

Mastering the Mist: Combating Downy and Powdery Mildew with Innovation and Tradition


Quality-conscious wine producers in Portugal employ a comprehensive approach to manage downy and powdery mildew, a pervasive and destructive fungal disease favoured by wet and humid conditions. Downy and powdery mildew can severely impact grape quality and yield, making its management crucial for maintaining high-quality wine production. Here’s how these producers tackle the challenge:

1. Vineyard Design and Management: Proper vineyard design and management practices are fundamental in preventing downy and powdery mildew. This includes selecting well-drained sites, optimising row orientation for maximum sunlight exposure and air circulation, and employing training systems that keep grape clusters dry. Pruning and canopy management reduce humidity around the grape clusters, making the microclimate less favourable for downy mildew development.

2. Resistant Varieties and Rootstocks: While the search for entirely resistant varieties continues, some producers experiment with rootstocks and varieties that show less susceptibility to downy and powdery mildew. This approach can reduce the disease’s impact and the need for chemical interventions.

3. Monitoring and Forecasting: Advanced monitoring and forecasting systems help predict downy and powdery mildew outbreaks. By integrating weather data and disease models, producers can identify critical periods for infection and apply treatments more effectively and efficiently.

4. Cultural Practices: Cultural practices, such as cover cropping and soil management, enhance vineyard biodiversity and soil health, indirectly supporting plant health and resilience against diseases like downy and powdery mildew.

5. Biological Control: The use of biological control agents, such as beneficial fungi and bacteria that inhibit downy and powdery mildew, is gaining traction. These biological products can be part of an integrated pest management (IPM) strategy, reducing reliance on chemical fungicides.

6. Fungicides: When necessary, fungicides remain an essential tool for managing downy and powdery mildew. Quality-conscious producers opt for targeted, judicious use of fungicides, focusing on critical periods and adhering to sustainable practices. They also rotate fungicide classes to prevent resistance development.

7. Integrated Pest Management (IPM): IPM is a holistic approach combining multiple strategies to manage downy and powdery mildew sustainably. It includes using resistant varieties, biological controls, cultural practices, and chemical treatments as a last resort to minimise the environmental impact and preserve grape quality.

8. Organic and Biodynamic Practices: Some producers follow organic or biodynamic practices, using only natural products and treatments to manage downy and powdery mildew. This approach aligns with a broader philosophy of sustainability and environmental stewardship.

By employing these strategies, quality-conscious wine producers in Portugal can manage downy and powdery mildew effectively, ensuring the production of high-quality wines that reflect the best of their terroir and varietal character.