Hi there, I was waiting for someone else to reply and hopefully some of our tree experts will chime in. Can you send in a pic of some of the leaves? Are they evenly distributed all over the tree or on the side near the aphid infested sunflower? Are you sure the ash itself doesn't have aphids? I'm sure you know that aphids secrete a liquid waste called honeydew and if it builds up on leaves black or brown mildew can form on it. It sounds like you're already a bit suspicious of that so let us know if you think the tree itself has aphids and whether the spotted leaves are on the sunflower size.

A tree that size must have been expensive. If it was mine, I'd snip off a small stem that shows symptoms and take it in to where I got it, or to a reputable local nursery.

Let us know what you think and how things work out. Good luck!

Grant

Well, the sunflower is gone now. I don't think the leaves have mildew on it, but they are pretty high up so I can't tell. They just look like dry patches on green leaves. They are all over, but fortunately they are now just about only on 5% of all the leaves. I'd bring in a sample to nursery, but they don't seem very helpful.

Toucan,

Aphids have piercing/sucking mouthparts that they use to pierce the cells of leaves or stalks and sip fluids. The symptom of this is usually a 'stippling' or tiny dry dots on leaves - usually a lighter color because the fluid is gone. The aphids leave behind 'honeydew' - a polite word for aphid poo. It has a high sugar content and ants love it. It often turns brown or black due to a mold that grows on it.

There is an aphid that targets ash trees called the wooly ash aphid. It is large and fuzzy white due to a protective coating that it excretes. I'm sure you would have noticed these near the new growth on your tree. They are usually active in April or May.

I think the brown spots are due to something else. It may take some detective work to figure it out but the main issue is whether the spots are getting larger and if they are located on younger or older leaves. If the tree is producing new shoots or leaves and the spots are on older leaves, I wouldn't worry. It could just be a symptom of stress caused by weather, fertilizing, watering, etc.

Ash trees need lots of water, but not necessarily frequent watering. You may want to invest in a simple moisture probe to be sure you aren't over watering. If your soil is well saturated, you may be able to extend the interval in between waterings a bit. Using a layer of organic mulch on top of the soil (but not piled up against the trunk) will slow evaporation and keep the soil cooler.

I hope this helps.

I was trying to post a picture of the leaves. How do you post the picture? No way to upload it.

Actually, I did notice today some very small white fuzzy things, probably aphids(?)along some of the leaves. I tried spraying them off, but they still stuck. There aren't that many of them now, but I know it's just a matter of time. I hate aphids. Any other way to get rid of them.