This is the third year in a row that I have failed at raising cucumbers and tomatoes. In previous years, the tomatoes have suffered through fusarium wilt and a squash borer moth that lays eggs in the cucumber vine stems. (See an earlier post on the “wasp moth” for more details on this pest.) But this year, perfectly healthy plants have just wilted over the course of one day with no apprarent cause.
The cucumber plant on the left looked fine yesterday, but is wilted this morning. Plant on the right is still looking healthy so far.
The same thing is happening here, but the tomato plant on the right has been looking poorly for several days and today is completely wilted, while the tomato plant on the left looks fine.
In addition to checking out my soil moisture, I also checked the cucumber vines for the presence of a bacterium that causes wilt. Cucumber beetles that lay their eggs and feed on the young stems and leaves of the plants harbor the bacteria in their gut and inject it into the plant stems as they feed. At high density, the bacteria then clog up the plant vessels that transport water, so the plant wilts. I tested for the presence of the bacteria by cutting the stems of wilted plants and squeezing out the xylem and phloem — no milky, sticky exudate appeared, so I don’t think bacterial wilt is the cause either.
Anyone have any ideas about what is going on here? I think the only thing one can do about this is to not use the garden space for a couple of years until the soil biota that are causing the problems disappear.
Back Yard Biology 
Dear Sue, I have been enjoying your blog for several weeks now, and I have a suggestion for you. Several years ago I was having the same issues. I solved them by planting my tomatoes and squash in big pots. I am also using a very good product to ameliorate the soil before I plant. It is: Jobe’s Natural and Organic fertilizer for vegetables and tomatoes with “Biozome.” In New Mexico it is available at Lowes. I don’t know about Minnesota. I also dose them with epsom salts when they are well started. The secondary advantage to pots is that you can bring them inside when the weather turns cold and enjoy home-grown tomatoes well into the Fall!
Thanks so much for the information, Pam. I knew I would have to resort to pots soon because of the fungal spores that stay in the ground for several years, waiting to infest the vegetable crops. I have two additional questions: what is “biozome”, and what is the purpose of the epsom salts?
Biozome is a collection of micro-organisms and beneficial bacteria. I use it for everything and have been very pleased with it for flowers as well as vegetables. Epsom salts are predominantly magnesium and I read somewhere that they were good for tomatoes. I tried it and my tomatoes seem to be delighted!
Wish I could help, but I am pretty much a plant killer!
Sorry to hear about the garden woes, but, alas, I am clueless about gardens.
There are so very many different things that can cause these issues that it’s really impossible to tell from here. It could be anything from too much water to insects to disease. I’d ask my local extension service. That’s exactly what they’re there for.
I would try a few in sterile soil next year just to see what happens.
My cucumbers aren’t looking very healthy this year – I’m blaming it on the cool weather. Past problems have either been bacteria wilt or aphids. Or so I believed. I’m curious now as to what caused this.
I have been battling the squash vine borer for years and years. I’ve tried everything and the only solution was to delay planting the zucchini until after the moth left town. (One year I even performed surgery and cut the grub out of the vine, but we won’t go there right now.)
I am trying straw bales this year, I put them in a place that does not get enough light but I am impressed with the plants so far. Check out my backyard, it may be your solution to icky soil.
I will certainly do that Irene. A friend on the other side of Lake Judy also raved about the straw bales. I should have tried that this year, but I got a late start with the garden this year due to too much traveling early in the summer.