here's another photo of the actual leaf, once infected by the bugs.

Here is a link that might be useful: {{gwi:1300987}}

Heat will cause blossoms to drop without producing fruit.

Re the bugs, see if the bug in this pic is what's on your plants:
http://axp.ipm.ucdavis.edu/PMG/r783303011.html

I found that page via the "Tomato Problem Solver" thread here in the Pests & Diseases forum.

Also check the undersides of the leaves, with a magnifying glass if necessary, to see if there are any mites or psyllid nymphs there.

Mites are very tiny pests that will cause leaf damage similar to what you've pictured. They are a problem in hot, dry weather conditions. Psyllid nymphs are the immature stage of the bug that might be in your pic.

Here is a link that might be useful: Tomato Problem Solver thread

thank you bcday. I appreciate your help! I think you may be right about that bug.
Doesn't seem like an easy way to get rid of them after they have overtaken the plant... Darn.