preventing wilt diseases next year

This summer my cucumber plants were thriving -- until one day the leaves began to turn yellow and die. It spread rapidly and within a week my crop was gone. It effected my squash and gourds to a lesser extent. Research led me to believe it was a form of wilt. My tomato plants also had serious problems and I had the worst crop in years. I think that was due to a huge amount of rain in June leading to a fungal disease.....So, is there a treatment I can use on the soil this fall to lessen the chances of the same diseases next year?

No treatment that I am aware that is available to home gardeners. Fumigants do work in some cases. With cucumbers odds are it is a an insect vectored disease. Control, especially of cucumber beetles will take care of the problem. http://www.ext.vt.edu/departments/entomology/factsheets/cucbeet.html
With other types of plants like watermelon, tomatoes a wilt resistant cultivar helps. http://plantpathology.tamu.edu/Texlab/Multicrop/wilt.html

Thanks for your overview and suggestions. Do you have personal experience with either of the methods described for dealing with the striped cucumber beetle?

I am not organic, so cuke beetles either spotted or striped are easily controlled with commercial insecticides ( Carbaryl, Endosulfan). Organic growers can use Pyrethrin/Rotenone.

farmerdill..... Question: Do Spotted Cucumber beetles chew on mustard greens? I have a yellow/black spotted beetle attacking my mustard. Soap solution spray seems to get rid of most of them.

never had any problem with spotted cuke beetles doing much eating. Thier worst damage is spreading bacterial wilt in cucurbits.Harlequin bugs will do a number on brassicas and they they like to work in cool weather. Most damage in warmer weather is flea beetles, leaf hoppers, and cabbage worms. All will eat mustard, but it is not thier favorite.

farmerdill..... You are probably correct & the most likely identification is Harlequin & not spotted Cucumber beetles. I will take a closer look to correctly ID the critter. They are definitely not leaf miners, flea beetles, leaf hoppers or cabbage worms.
THANKS!!

I have never used Sevin on continuously flowering plants, like cucurbits, because of what I perceived to be a risk to the pollinators. Is this a false concern?

Sevin, like most insecticides is very hazadous to honey bees. After all they are also an insect. Sevin (Carbaryl) is a contact insecticde with a very short life in liquid form. Sprays can be used late in the day after the bees quit working and will not be dangeous to them when they return in the morning. The dusts however are moisture activated and can linger around until the are activated. It is a good policy to NEVER use dust on a cucurbit. Even the sprays are touch and go. If you are not very carefull or if you are unsure, don't use Carbaryl on cucurbits. That goes for just about any other insecticide that will take out cuke beetles or pickleworms.

There is a variety of cucumber that is bacterial wilt resistant. It is "Country Fair." I have grown this for 4 or 5 years. It is somewhat like a pickler type, needs a fair amount of water and needs to be kept well picked as it has a tendency to only do one fruit per major vine segment. We have serious problems with this wilt here, and I tried a number of methods, without major success, until switching to Country Fair. I have a neighbor that never has a problem with wilt and gets lots of cucumbers without using Country Fair but he uses Sevin a lot , plus I have noticed that sometimes the beetles will miss certain areas - not sure why.

This link has a list of resistant varieties (few) as well as some other strategies for controlling this problem. Cleanliness and rotation are important, but where I am at is near some woodsy areas that have wild members of the cucumber/melon family that host the beetles.

http://www.extension.umn.edu/yardandgarden/ygbriefs/p260cucurbit-bactblt.html

Country Fair is a decent cucumber well worth trying if you have wilt problems.