Any ideas on what this could be? The system is new. Just added fish a few days ago. This is only found on the 6 tomato plants that I grew from seed and is on the lower leaves. The 2 transplants that were purchased from the store do not have this on them. I am thinking it may be a disease but want to see other opinions before pulling all 6 plants from the system.
Thanks in advance!
That looks like a really good photo, it might be worth sending to your Agricultural extension to see if they can identify the problem.
I did a quick search to see if I could find a picture of a problem that looked like this but it is hard for me to tell.
here is one of the links I looked at.