Black Krim are always disease magnets in my garden!!
Roma VFN is doing super, Cherokee purples are hanging in, Brandywine's always wain on me by mid summer. If the plant is healthy I cut it back, spray it with some neem (especially where i cut it back) and then let it grow back for fall harvests.
Juliettes, Sungold, Rutgers, sweet 100, Taxi and Creole are all having a hayday in the heat. Some of the other canning tomatoes are very very stressed but I'm also cutting back, spraying with some neem (as a fungicide) occasionally and seeing if I get some later harvests when the nights get a bit cooler again.

My Cherokee Purple and Brandywines took the month off. I'm cutting back too. Peppers are doing okay.

girlgroupgirl:

Would you mind sharing your method for cutting back mature tomato plants? I have several that have slowed way down which might benifit from pruning as the weather cools,(if it ever does).

Larry

gardengolfer:
for healthy tomatoes plants, just cut back to 1/2 of the size of the plant - do this in the evening and if the plant is totally healthy I prune it back and then wipe down whatever you cut with, with some rubbing alcohol. Then I "wash" my hands with the alcohol (or wipe) and include the handles of the cutting tool. In this weather I would spray on some neem, diluted to whatever the bottle says is the fungicide rating or some Safers fungicide (or whatever you like that is safe for food plants). This is just some insurance on those cuts.
If the plant is not healthy like 99% of mine are not, I wipe the blade after EVERY cut. Then, because unhealthy bits of browned and dying foliage could have fallen on the mulching material I spray the mulch with the neem oil. All I want to do is stop those spores from bouncing back up in rainy weather, so I coat them with oil, well. It is a time consuming process and can not be done in the AM etc. as you don't want to expose those new cuts to high temps and a lot of sun - give 'em a chance to callus over.
This method has worked really well for me. The plant tends to produce another good size crop of tomatoes. If the plant is just left it will probably produce again but the tomatoes tend to be small. Don't forget that in a few days after pruning you can fertilize your plant again and water well to keep it happy and growing!

girlgroupgirl: Many thanks. Your answer is most helpful.

Larry

cherokee purple, brandywine hanging in there. lemon drops are prolific!