How to Prevent Powdery Mildew in Vineyards | Effective Oidium Control Strategies for Grapevines

If there is one endemic disease in Spanish vineyards, it is powdery mildew (Erysiphe necator), also known in different regions as ash disease, white mildew, or “cenicilla.” This fungus affects leaves, grape clusters, and shoots, causing significant crop losses both in yield and in the quality of the wine produced from affected grapes.

Prevent or Cure? The Grower’s Dilemma

One of the main questions winegrowers face every season is when to act: should treatments begin before symptoms appear, or should they wait until the disease is already visible?

Experience and agronomic knowledge provide a clear answer: prevention is always more effective than cure.

Understanding the Powdery Mildew Cycle

Effective powdery mildew control starts with understanding its biological cycle. The fungus survives winter as mycelium or cleistothecia in plant debris and buds, becoming active when favorable conditions of mild temperatures and moderate humidity return.

Anticipating this critical moment is essential to avoid primary infection and limit the spread during later stages of vine development.

Preventive Measures Beyond Chemical Treatments

Prevention does not only mean applying fungicides. It involves integrated vineyard management practices aimed at reducing the conditions that favor fungal development:

Proper vineyard design to ensure good air circulation and avoid waterlogging. 

Selecting varieties that are less susceptible to powdery mildew (for example, Merlot is generally more tolerant than Cariñena). 

Avoiding excessive nitrogen fertilization, which increases vigor and susceptibility. 

Applying canopy management practices such as leaf removal and shoot thinning to improve ventilation. 

Removing pruning residues after winter pruning to reduce inoculum sources for the following season. 

 

Advantages of Preventive Plant Protection

From a plant protection perspective, prevention reduces fungal pressure and lowers the number of spores capable of infecting the crop when favorable conditions occur.

In addition, as the availability of synthetic crop protection products becomes increasingly restricted, preventive strategies help minimize the risk of resistance by avoiding repeated applications from the same chemical families.

Conclusion: Prevention Means Better Production

In modern viticulture, prevention not only protects the harvest — it protects the future of the vineyard.

Combining responsible agronomic practices with preventive control strategies is the best way to maintain vineyard health, reduce long-term costs, and ensure higher-quality wines.

AFEPASA Commitment: Expertise in Vineyard Protection and Nutrition

At AFEPASA, we understand the importance of sulfur as an essential tool in powdery mildew prevention. With more than a century of experience in developing sulfur-based solutions, we offer effective, safe, and sustainable products adapted to the demands of modern viticulture.

From traditional formulations to advanced concentrated suspension technologies, AFEPASA’s portfolio supports winegrowers throughout every stage of the crop cycle, helping maintain vineyard health, protect wine quality, and promote more responsible and efficient agriculture.