Q.Yellow Spots On The Edges Of Lilac
I’ve noticed white spots on my lilac leaves and my lavender has also developed white tips on some of the leaves. The infection (?) seems to travel down the length of the lavender leaves leaving it completely bleached out. I have attached photos in the hope that you can identify the culprit and advise me of the action I should take please.
Certified GKH Gardening Expert
Lilacs are notorious for getting powdery mildew, but it doesn't usually cause a problem with them. More sun will help and pick up any fallen leaves. Pruning could help with air circulation.
The lavender looks like something else. It could be leaf scorch from too much sun. Did you bring it outside after overwintering inside?
https://www.gardeningknowhow.com/plant-problems/environmental/leaf-scald-in-plants.htm
https://www.gardeningknowhow.com/ornamental/shrubs/lilac/powdery-mildew-on-lilac-bushes.htm