Guangdong Kinen Sanitary Ware Industrial Co.,Ltd. , https://www.kinengroup.com
Grape downy mildew is a common and destructive disease that affects grape leaves, causing yellow or brown polygonal spots. Under wet conditions, a white, frost-like layer often appears on the underside of these lesions. As the disease progresses, the affected areas turn brown and dry, significantly impacting grape growth and yield. Prompt application of **pesticides** is essential to prevent severe losses.
The disease typically occurs in autumn, and its development is highly influenced by weather conditions. The ideal temperature for spore germination is between 10°C and 25°C, with relative humidity above 95%. These conditions are often met during the fall, making it a favorable season for the disease. In addition, many farmers fail to implement timely management and preventive measures. Poor air circulation, lack of sunlight, and failure to remove infected leaves contribute to the spread of the disease. Delayed treatment in infected areas is another major factor that leads to outbreaks.
To effectively manage grape downy mildew, several control measures should be taken:
1. **Orchard sanitation**: In late autumn, collect and remove diseased leaves and fallen foliage. Cut off any infected shoots and properly dispose of them by burning or burying them to prevent further spread.
2. **Orchard management**: Improve air circulation and reduce humidity within the vineyard. Farmers are advised to plant in a north-south orientation, choose elevated areas, ensure proper drainage, and prune regularly. Removing unnecessary branches near the ground helps increase light penetration. Applying appropriate amounts of phosphorus and potassium fertilizers, along with increasing calcium content, can enhance the plant's resistance to disease.
3. **Chemical control**: Since downy mildew thrives in high humidity and low temperatures, early detection is crucial. When daytime and nighttime temperatures average around 13°C and there is rain or fog, the risk of infection increases. Spraying should be done as soon as symptoms appear. Recommended fungicides include: 72% DuPont Kocide (72% mancozeb) diluted at 500 times, 64% antibacterial powder at 500 times, 85% Aluminum Phosphate at 400 times, 25% Metalaxyl at 500 times, and a 1:1:180 Bordeaux mixture. It’s important to spray thoroughly, especially on the underside of the leaves, and alternate between systemic and protective fungicides to avoid resistance.
By combining cultural practices with timely chemical intervention, growers can significantly reduce the impact of grape downy mildew and protect their crops for better yields and quality.