Roger I have the same problem when spider mites are starting to attack my plants. You cannot see them with the naked eye when they 1st are populating the plant. Check the undersides of the leaves real good and tap them on a piece of paper. If you see small dots moving this is your problem. Also seen it from excessive sunlight. You might note the location of the affected plants vs the non affected ones. Your leaves are still green so you are on top of it before it becomes a problem. Jim

Dave, Have you actually determined that you have a fungus problem? Have you determined that you COULD have a fungus problem in the future that you need to guard against? I'm not a big fan of the 'organic' no-spray method and firmly believe in 'better living through chemistry', but you should actually only use it if and when you have determined that is actually a fungus problem. Daconil and the other crap often recommended to be sprayed are poisonous you to and everything else around you. Why saturate your environment when you don;t really need to. Many of the people on GW live in environments where gardens were never intended to grow and they are fighting an uphill battle all the way. On the other hand, we have this wonderful semi-arid desert to grow in, and we have out own problems, like high winds and hail infestations :) We rarely ever have problems with the bacterial infections because it is just too dry. I have lived here all my life and the only thing me or my family has ever had to deal with were mosquitoes and miller moths. --->Rob

I'll defer to the more experienced growers, but from what I've read/heard, the bottom leaves yellowing is normal. I think most varieties do it.

Yes, that looks like sunburn. The newer leaves should be fine. Once enough new leaves emerge to support photosynthesis for the plant, cut off the old, damaged ones.