Gardening woes

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.

What’s wrong with the coneflowers?

Have you seen flowers like this in your garden?

Instead of making flowers, the coneflowers are making tufts of green leaves.  Their flower-making potential has been damaged by a mite that infests the base of the flowerhead.

In some of the plants, the leaf tufts lie on top of the normal flowerhead, and in others, the flower head has been completely reprogrammed to produced just leaves.  It seems that the mite has completely modified the genetic program.

Fortunately ,the mite infestation has only occured in a small proportion of the flowers in the garden this year, but once the mite appears, you need to be careful to remove infested flowerheads and old vegetation from infected plants in order to reduce the mites’ impact next year.  See this article from the OSU extension program about the mite problem.