Diagnosis: Probably herbicide injury
On Monday I checked on an ash tree for a client in East Greenville. She said the leaves appeared to be wilting.
Well, they didn't really look wilted to me, but they were distorted and curled.
I unrolled some of them to check for pests; none were there. No aphids, no silk from any caterpillars. There was an outdoor fireplace nearby. But if that were the cause, I would expect the symptoms to be the worst closest to where the fire would have been.
Next to the ash is a young saucer magnolia. Last year I treated it for a bad magnolia scale infestation; so while I was there, I examined it. The scale was gone, but it too had a lot of distorted leaves. And, like the ash, no pests, no aphids.
When trees of different species have the same symptoms, it's probably abiotic - not a disease or a pest. Pests and diseases are usually host-specific. Near the ash and magnolia is a Kousa dogwood. Same thing - distorted leaves. And the type of distortion that is generally seen with certain herbicide poisoning. That is, elongated parallel veins and interveinal chlerosis.
There is another ash a few hundred feet away also at the rear of the backyard. It has the same symptoms, only even more pronounced.
Well, all the symptoms are consistent with the effect of herbicides, but the client's lawn is definitely not weed free. If that is the cause, the likely reason is spray drift from the hay field adjacent to the yard. The field looks very clean, hardly any weeds.
So that is my theory - all the trees were damaged by herbicide drift from the application to the hay field. And that is what I told the client. And she confirmed that the field was recently sprayed. She will ask the farmer to be more careful in the future.