trees are quite susceptible to the fungus that causes powdery mildew. Affected
foliage slowly becomes covered with a white powder-like coating that is easily
brushed away. Older leaves at the bottom of the tree are usually affected
first, around July. If left untreated, powdery mildew will spread throughout
the tree and eventually cause the leaves to yellow and drop before the end of
the growing season.
1-Prune the lilac in spring immediately after blooming to remove
old, dead branches and increase air circulation. Poor air circulation
exacerbates powdery mildew. Because the entire bush is likely infected, pruning
out diseased branches is not practical.
2-Spray lilac bushes with a fungicide labeled for treating mildew
as soon as symptoms appear.
3-Repeat the fungicide application in two weeks, or as directed by
Examples of Fungicides(Myclobutanil - Neem Oil – Propiconazole
- Thiophanate-methyl )