Leaf Spot Disease
size and color of the spots largely depends on the type of bacteria at work; in
general, the spots are brown or black in color. Some are surrounded by dark
margins and others are marked by concentric rings. As the spots spread, they
form large blotches centered around the veins of the leaves. If the disease is
allowed to progress, the leaves will eventually yellow and drop.
1-Rake up and destroy plant debris
of lilac plants affected by leaf spot. Do not compost diseased leaves.
2-Spray leaf spot-infected lilac bushes with a Bordeaux-mixture
fungicide. Spray the plants on an overcast but dry day, following package
directions for proper application.
3-Make two more fungicide applications, spaced 10 days apart.
Examples of Fungicides (chlorothalonil
- thiophanate-methy )