Q.powdery mildew
Is there a home remedy for “powdery mildew” on my lilac bush leaves?
Certified GKH Gardening Expert
Yes, I like to mix a little rosemary, and neem oil together in some warm water and spray the plants. This is a safe and natural way to rid them of the mildew. Here is an article for more information: https://www.gardeningknowhow.com/houseplants/anthurium/anthurium-care.htm
There are several home remedies but research is not all that encouraging on effectiveness. Neem oil is one you might try although it is said to be better at preventing fungal infection than treating it. 5% apple cider vinegar, 3 Tbsp, in a gallon of water is another: spray tops and bottoms of leaves every 3 days X 3 applications. Baking soda spray: 4 tsp baking soda, 1 Tbsp horticultural oil OR citrus oil in one gallon water. Spray leaves every 3 days X 3. Lilacs are prone to powdery mildew. Prune it to allow more air circulation: remove up to 1/3 of the largest branches annually after blooming and remove most of the small shoots that arise from the base of the plant as well as suckers. Water deeply during hot, dry weather to prevent re-infection. Clean all plant debris after leaf fall and do not compost these leaves.