Listed below are some natural remedies which can help in treating powdery mildew.....
1.Milk: Diluted cow milk 40% + water 60%. Mix well. Spray weekly once.
2. Garlic: In a mixi blend 2 to 3 bulbs of garlic with some water and add 5ml soapnut solution to this. Strain and keep aside. Take 10ml of this concoction to a litré of water and spray.
3. Water: Just simple watering will wash away the mildew...give your plants a good rub dub.
4. Baking Soda: 1 tbsp baking/cooking soda + 5ml neem oil + 5ml soapnut solution + 3-4 litres of water. Mix well. Spray once in 15 days.
5. Vinegar: 1 tbsp vinegar in 1 litre of water. Mix well and spray weekly once. Be careful not to spill over to other healthy plants élse they could die.
6. Prune: Over crowding and poor air circulation will also result in mildew.
7. Copper Buttermilk Spray: Soak copper wire or vessel in buttermilk, dilute ànd spray. Detailed recipe is there in my upcoming book Home Gardening - the Natural way.
8. Onions: Soak onion peels in water. Dilute and spray
9. Bio Fungicides: Pseudomonas florescence or Trichoderma viridi 20ml to a litré of water when sprayed will work wonders.
10. Turmeric: Diluting little raw milk with turmeric powder and water and spraying will hélp control powdery mildew.
11. Ash: Make a concoction of 1tsp ash + 1 litre water + 30ml raw milk. Mix well and spray.
Happy Gardening!!!!