Bacterial leaf spot, common and controllable, you just have to act on it quick because it will spread. It starts in the soil, then splashes up onto the leaves, and gets worse every time the leaves get wet. Excluding rain, always keep vegetable plant leaves as dry as possible, try not to wet them with a hose. It can also spread by touch, both on your hands, and on your pants.

A couple of things you can use to treat it. Copper, Serenade.

Copper products = Ortho Disease B Gone Copper formula. They sell a concentrate bottle that's a great bang for the buck. Get a $10 1 gallon pump sprayer and follow the directions on the bottle.

Serenade = Serenade Garden Disease Control. A concentrate bottle is available. This uses a special bacteria that clobbers the nasties on vegetable plants (biological control that works pretty well in my experience). Again the concentrate would require a pump sprayer.

You would spray all leaves on all plants, the tops and underneath. In my experience, once it gets past a certain stage it isn't 100% curable, but you can control it enough to get a full crop. If you let it go without treatment, your plants will lose 3/4 of their leaves and photosynthesis will be reduced (along with a reduced crop). I would do a walk around and rip off a couple of the most raggedy leaves off each plant. Just be mindful not to spread the bacteria to other plants. I've been battling it for a few years now, i notice that neem oil doesn't work very well on it, not as good as the products i posted above anyway.

Sometimes, if only one plant is *heavily* affected, i'll yank it from the ground to spare my other plants.

Good luck either way.

Edited and deleted some info to reflect robeb's important correction posted below (thx !!)

This post was edited by sjetski on Wed, Jun 12, 13 at 9:43

If it is bacterial leaf spot don't waste your money on chlorothalonil - daconil.

Daconil is a fungicide to be used as a preventative for fungal leaf diseases, not as a cure for bacterial or any other type of leaf problems after they occur.

My apologies,. I haven't used Daconil in years. I do remember it as a good product, but my plants may have had other issues at the time.

This post was edited by sjetski on Wed, Jun 12, 13 at 1:56