I've battled early blight (and usually lose) and all the other fungal diseases. The normal recommendation include hygiene practices (trimming lower leaves, mulching, removing infected leaves, etc, and spraying With daconil or copper. In spite of all the work, none of this seems to help that much. The summer/fall, I tried spraying with a dilute bleach or hydrogen peroxide solution every other day. My tomatoes are mostly defoliated and suffering badly. I may get a handful of small Big Beef tomatoes in November maybe.

The University of Minnesota downplays Daconil and copper also.

Common fungicides for control of early blight on tomato.
Fontelis very good
Mancozeb (Manzate) good
Daconil Fair
Kocide (copper) Fair
https://extension.umn.edu/diseases/early-blight-tomato

There appears to be a solution the commercial growers are starting to use. Here's a powerpoint from the University of Tennessee:

file:///C:/Users/dwsta/Downloads/tomato%20spray%20program.pdf

The most intriguing method is alternate weekly spraying with Fontelis, Manzate (mancozeb), and Kocide (copper). This spray regimen eliminated about 99% of early blight diseased leaves.

Mancozeb and copper are relatively cheap but Fontelis is only available in 80 oz jugs and the cheapest price I've seen is $135. Still this would seem to wipe out Early Blight.

Maybe some of the commerial growers could chime in with their thoughts.

I think ground temps play a big roll.
Most research is based on in the ground directly planting.
A neighbor has a tall raised bed and his plants are always as green this time of year as when he planted them.

Investing in polytunnels or better is the way every commercial grower does it around here.

mama_lor wrote: ↑Tue Oct 12, 2021 10:26 am Investing in polytunnels or better is the way every commercial grower does it around here.

I'm not sure how that would prevent an airborne fungal disease. This Fall I'm growing in pots on my patio and in a new raised bed and I am plagued with early blight.