The giant crape myrtles on either side of my front door are full of some kind of leaf spot. It starts off as little yellow spots, then the whole leaf turns yellow/brown and falls off. I think it may be cercospera. I have sprayed twice with Thiophanate methyl (Green Light Systemic Fungicide). The trees are very tall, so I got up as high in the tree as I could with my sprayer, and drenched the lower leaves.

Can someone help me? I got the Thiophanate recommendation from a website regarding crape myrtle care, but I'm not sure if it is the right product because it did virtually nothing. The trees grow so vigorously every year, but each year they either get full of aphids and the resultant black mildew, and this year they have been half defoliated by the leaf spot. They also flower very poorly.

PLEASE HELP ME!!!