I suspect solarizing will be of limited value in your climate. The technique was pioneered/developed in Israel and works well there.

If it is fusarium, you will have better success using plants which are resistant to that fungus, along with a 4-yer rotation of plant families in your garden.

Thanks Jean. I am working on both of those for the future.

I'm glad that Jean mentioned something about the solarization. It would be a waste of time in your location and requires several long weeks during the hottest, sunniest time of the year. The soil needs to be prepped, weed and debris free, and the clear plastic must be applied tightly and sealed all the way around.

I doubt that it would be a worthwhile project in your part of the country ever, let alone when the days are getting shorter and the temperatures cooler.

Have you ever considered parasitic nematodes? Your university extension service does nematode assays as well as plant pathogen tests.

No I haven't rhizo. I'd have to look up the symptoms and see if nematodes make sense. I have never dealt with them before.

Here are the stems of the basils I pulled up a few days ago. The brown color working its way up into the green seems to be a telltale sign of Fusarium.

It's been a little longer since I pulled the green beans but they too have brown stems near the bottom.

This volunteer cherry tomato did so well early on and got loaded with fruit. Then in July-August the blight hit it hard and fast. From the bottom. I always figured I had standard 'tomato blight' but it could be Fusarium also?

I found a MO fact sheet on nematodes that lists crops that are highly susceptible all the way to very tolerant in 4 grades.

http://extension.missouri.edu/p/g6204

I have some plants that do not do well for me but are supposed to be resistant or even benefit from nematodes. Rhubarb and asparagus. Now most of the 'very susceptible' crops - all the cucurbits, peppers, tomatoes - do fairly poorly for me, so that fits with nematodes. But I am growing okra for the first time, and it's doing very well. Actually though it's in a bed with 4 tomatoes that are also doing better than average. I may have found one bed at least that is not loaded with whatever this is. :-]

When pulling plants, I do not see a lot of root knots and nodules like the pictures show. The basils and beans in the above pics have very normal looking roots.

And of course the pepper plant that got me working on this problem again in the first place.

Not all parasitic nematodes are root nodule forming. Decline, wilt, yellowing, brown lesions on roots and stems, for example, are typical symptoms of nematode damage.

Just a suggestion, mind you, and one that can be checked with a soil test for nematodes. Your Extension service can help you with this as well as testing for

I'm thinking I need to call them and see what they can do.

Decided to check in on this thread...ironically the day I posted that, I looked up the University lab, and their pest identification page had a huge notice that they were closing down for a month (or three, I forget) due to some kind of reorg or remodeling. Can you collect this kind of a sample in winter?