Please post more images. Start with the tree overall, and an entire affected branch.

Here are a few more photos. I'm not sure if the insect is relevant, but I saw several of the same insect on quite a few leaves yesterday (didn't see any this morning).

http://dl.dropbox.com/u/40330907/Art%20-%20Indoor/photo-12.JPG
http://dl.dropbox.com/u/40330907/Art%20-%20Indoor/photo-11.JPG
http://dl.dropbox.com/u/40330907/Art%20-%20Indoor/photo-8.JPG

Kevin

Your pics:

The insect -- a fly -- isn't damaging the tree.

As for the red leaves, I agree with Ken. But if they're blackening then dropping, something is wrong. Perhaps water -- too much or too little?

But you said "later in the summer" which could be an entirely different problem such as in a leaf spot disease of one kind or another. Post images of that when it occurs.

Thanks Jean. It's a relief to learn that nothing is amiss at this point. Will definitely re-post if things change.

Kevin

It's been 2 months since my original post. Quite a few leaves have rusty and/or black spots on them and quite a few have already dropped onto the ground.

It's been a hot, dry sum me and I've been drip irrigating every other day at 6am.

Any thoughts?

A tree like that has been in the ground for a couple years shouldn't need extracurricular watering unless it doesn't rain for more than a month. If your grass is still alive, it's not dry enough to worry about trees. I would turn off the irrigation. Light watering done very often like that can cause the tree to make too many weak roots near the surface instead of seeking water deep below ground, as they are supposed to. If/when your tree genuinely needs water added, letting it drip slowly all night would be best, then wait weeks to do it again (if it still hasn't rained.)

Thanks Purpleinopp. - I've backed off the watering.

Do you think that this alone will prevent the recurrence of the leaf turning rusty and dying next season?

Kevin

...looking for my magic 8 ball...

I'm always highly suspicious of drip irrigation. I don't think that many people know how to measure output....or even how to set up a drip system for trees. Perhaps your soil is getting dribbled on in a few places....but never enough to soak the soil? It's possible to run a drip system every day and still leave the soil/root system parched.d