There is nothing you can do to ensure it doesn’t happen again and no matter what you do a fungi spore can easily blow in and take hold in your garden. Odds are high a fungus and not bacteria took over your garden and the spores will overwinter in the soil on dead plant debris, so the first thing to do is clean up the beds, not leaving a speck of leaf debris on the ground.

Steps I recommend and do; Cut the plants off at the base with just a stub showing. Dispose of all foliage, dead or alive never to be seen again. DO NOT work anything into the ground, this is what the fungi spores cling to until next season. Use a propane torch similar to the one in the link and Torch the entire bed. If generates 3000 degrees and will kill every blessed thing on the soil surface in a fraction of a second and very effective. When done torching pull out every root ball from the ground and dispose them. You've eliminated all new sources of Fungi spores and pulling the roots has reduced nematode populations feeding on the roots. Nematodes feed and cause root damage which can become infected with a bad Bactria.

If you still have energy left turn the soil and hit it again with the torch to kill more spores and nematodes. Planting in the same space every year causes large populations of these nematodes and spores to build up and using the torch would be similar to solarization as Dan said, but done in just a day. Now if you have any time or energy left turn the soil and flame again. Now you're ready to work the soil and add what you wish.

I torched my 75' by 40' potato patch this morning, (potatoes still in the ground) to kill everything on the debris and to force the potatoes to set a thick skin before harvesting in two weeks by stopping any vine growth now. I'll do what I recommended for tomatoes except turning the soil and flaming again because I'm rotating them to a different area next year.

A plant with resistance doesn't mean it's immune, only resistant if the plant is healthy without environmental stress. Both weaken a plant making them easier for a disease to take hold so good care is important. Finally Start spraying next year with a fungicide when tomatoes start to set fruit every week or two which can stop any spores which blow in or splash up from germinating. If you don't want to spray then you need to scout your plants every day looking for the slightest sign a spore has germinated on a leaf and remove it. Once the spore germinates it grows in and feeds on the leaf until it's time to reproduce, and then will shoot thousands of spores into the air. Its hard but can be effective. Good luck.

Never thought of using a torch. Wow! That could certainly do the job quickly. But you need to get the heat at some depth, so you probably need to fire it for some time. How long does it take to torch your 75x40' patch? As noted, might be wise to turn the soil over after you do it, and torch it again. Also, I want to reinforce the point that spores can easily blow in and take hold in your garden. The point being that the areas surrounding your beds have also been infected with those spores, so if you replace the soil, that new soil will eventually get infected. By the same measure, sterilizing your soil may work for one season, but the stuff is all around you, so it's likely to come back. Keep that torch!

It took me about two hours for the 75'x40' patch and a 1/4 tank of propane from a 20 pounder. My prior post addressed turning/tilling the soil and repeating the process, and also air borne spores.

Agricultural Flaming is a common practice for a number of reasons. I Flame potatoes for many reasons and it makes a huge difference. It kills all vines so the potatoes stop growing and they go into dormancy so they set thick skins before harvest, and also makes harvesting so much easier. It kills any Colorado beetle larvae still on the vines and the heat also kills a lot larvae in the very top of the soil reducing the population. It also destroys all pathogens on the surface and the best benefit I love is it kills weeds along with any weed seeds dropped or blown in.

I have very few weeds in with the potatoes now and it was always a problem before I started flaming, and I'm telling you digging potatoes in a weedy potato patch sucks. I will more likely give the ground a once over with the flamer before I disturb the soil and bury any new weed seed before I dig the potatoes. Letting the potatoes set skin in the ground increases storage length and why commercial growers always kill the vines before harvest, I still have firm good potatoes in cold storage I'm still using to this day. I'm sold on flaming.

Thanks. Yes, my point about airborne spores was reinforcing the point that you made. Two hours for a few hundred yards isn't that bad. Sounds pretty doable.

After a little research, I gather that agricultural flaming is mainly for weed control, but also is understood to work on nematodes and fungal pathogens. It is interesting that for solarization, the recommendation is to make the soil highly saturated with water, but for flaming, best results are achieved when the soil is dry. That's probably because moisture driven off by the flame effectively cools the soil. With solarization, the heat is trapped under the plastic, even if it is moist heat.

Of course, there are both good and bad fungi, and biodegradation and soil nutrient increase depends upon the former. There is an interesting paper talking about recovery of fungal populations after a forest fire, where the surface temperatures, at least, are pretty horrendous. They find that below about 4-inches, populations aren't seriously impacted, and recovery happens before too long.

Does growing in containers make a difference?

That is what I would do if that did

Sounds like a propaine torch this fall along with cleaning up remants of old plants is my best bet.

i do try to only grow plants from seeds that are resistant, but i guess that only does so much.

Mike, im not sure what you mean? i think id have the same issues and then have a bunch of containers eveeywhere haha.

"Does growing in containers make a difference?"

I think so :-) I have always ever grown all my toms in containers (25-30 years?) and I have yet to encounter any serious fungal or bacterial issues. For an annual crop like most veg, fresh soil media each season pretty much assures no fungal spores lurking in the soil or any overwintering debris.

But then I don't grow scores of plants of a huge variety either :-)

It should be noted that such a strategy might be problematic with raised beds bounded by wood. Same with wooden containers. That's a good way to incinerate the borders. Then again, one could blast the middle of the bed, and then rake a pile of soil to the middle of the bed, and blast again. Proper stirring could yield the desired result.

FWIW, my raised beds are composit material.

Re containers, there is nothing about a container that prevents their soil from eventually getting infected with bacteria or fungal pathogens. Certainly if you refill them every year with new, and ideally sterile mix, you're good to go. But who wants to do that?

Serious container gardeners do :-) Because very few packaged container soil mixes will hold up longer than a single growing season, they should be refilled with fresh soil mix annually. Custom mixes might work a bit longer but those are primarily bark and granular mineral mixes and nor great for tomatoes. And even those need to be replaced periodically.

Gardengal, if i was to do that with my raised beds, id need a dumptruck full of soil every year! i had some fresh soil yealry though.

Dave, a raised bed is NOT a container. One does not use a container soil mix in it and the soil does not need to be replaced each season, only refreshed. Containers - pots - were only suggested as an alternative to your raised beds in dealing with this problem :-)

Gardengal, you know i know this :) The raised bed is essentally an extension of the earth while the container is not.

Pots sadly would just add a lot of clutter to my yard. The beds are also visually appealing.

Im going to clean all plant materials well this fall, possibly torch the soil and add some fresh soil in the spring. ill also do what i can to keep the cucumber beetles in check.

I don't do container vegetable gardening, but I have loads of containers for other plants. I don't think I've refilled them in a decade, though as the organics decay I top them up with mostly compost. They're all doing great, but I'll admit that fruiting plants may need more firepower to do their best.