Downy mildew is a plant disease caused by oomycetes, which are water molds and not technically fungi. It is a common disease of many plants, including grapes, vegetables, fruits, and flowers. Downy mildew can cause significant yield losses and reduce the quality of fruits and vegetables. Downy mildew is a serious fungal disease that can infect all green parts of grapevines, including leaves, shoots, flowers, and berries. It is caused by the oomycete Plasmopara viticola, and is most prevalent in warm, humid conditions with frequent rainfall.
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- Type of Infestation: Disease
- Common Name: Downy Mildew
- Causal Organism: Plasmopara viticola
- Affected Parts Of the plant: Leaves, Shoots, Flowers
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Environmental favorable factors for pests/Diseases:
- Temperature: Downy mildew thrives in cool temperatures, typically between 15-23°C (59-73°F). It's less active at temperatures above 30°C (86°F) for extended periods.
- Humidity: High relative humidity (85% or higher) is essential for infection and sporulation. Free water on the leaf surface is necessary for spore germination and infection.
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Symptoms of Pest/Disease:
- Yellow or brown spots on the upper surface of leaves
- A white, gray, or bluish downy growth on the underside of leaves
- Stunted growth
- Wilting
- Fruit drop
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Measures to control Pests/Diseases:
Products
Technical Names
Dosages
Azoxystrobin 23 % sc
200 ml/acre
Mancozeb 75% WP
500gm per Acre
Metalaxyl 8 % + Mancozeb 64 % wp
1.5 to 2 kg per ha
Metalaxyl-M 3.3% + Chlorothalonil 33.1% SC
300-400 ml/acre
