Do I have a foliage disease
 

Hello all,
I've got a mixture of heirloom and hybrid plants growing both in ground and in earthboxes in Salt Lake City, UT. We're in the middle of a 2 week 100+ temperature streak. Humidity is very low, no rain, no overhead watering, but my tomatoes are kept well-watered with a drip system. Today I noticed on just one of my plants, an otherwise very healthy and robust 'Mexico Midget' (growing in an earthbox) the following foliage defects shown in these two images. None of my other plants have anything like this. I thought I'd poll the experts to see if I have something and if so, what I need to do about it.

Thank you for your time.

My guess would be yes, early blight. Some others more educated than I am on tomato diseases might chime in.

I wouldn't jump to conclusions about fungal disease which is not favored by those extremely hot/dry conditions anyway, Look for insect pressures or it might just be stresses caused by the high heat or physical damage from high winds,

What I tend to call environmental damage - wind and weather primarily. Like Ray said look for pests - aphids and other leaf suckers as well. See how the damage parallels the leaf veins? That usually means pests on the underside of the leaves.

I see some weeds in the pics as well and that often means insects are hanging around.

Also strip those leaves from the plants to make it easier to monitor future damage.

Dave

I agree with Ray and Dave... use a hand lens to look for pests on the underside of the leaves. Although I don't see the stippling usually seen with mites, the pattern is otherwise typical.

Good luck,
Steve