after the flood: tomato troubles in a wet year
T OMATOES ARE IN THE HEADLINES LATELY, particularly throughout the areas of the country where weather has been record or near-record wet. The gardener’s best-laid plans may not prove to be enough to guarantee a bountiful harvest, or so I fear, with the first signs of some ailment or other showing itself on some of the lower (older) leaves of some of my plants right now (above). But do I have early blight, or Septoria leaf spot, or Verticillium wilt, or (as the scariest headlines have already noted is upon us) so-called late blight? Will there even be a crop this year?
I actually have no certain diagnosis; so many of these issues look somewhat alike, unless you are a plant pathologist, and so far I only have a relative few affected leaves. I nevertheless love Cornell’s diagnostic tool, a photo-driven system arranged by plant part (leaves, stem, fruit).
What I do not seem to have, thankfully, is the late blight that’s been the source of the most dramatic headlines, and of a thorough story by Adrian Higgins of The Washington Post, late last week. This dramatic outbreak has also prompted warning bulletins from Cornell and other extension services. My plants have none of its characteristic early sign: dark stem lesions.
This is the affliction (affecting tomatoes and potatoes) that caused the 1840s Irish Potato Famine, and it has never been recorded this early in the United States, apparently, nor this extensively, with much of the East affected. Fears that further wet conditions will bring vast commercial-crop losses of tomatoes and potatoes are running high. Fungicidal sprays are the retaliation tactic (weekly Neem oil being the non-toxic choice) but even those may fail in severe cases, and if the weather helps the fungus to get an increasing edge.
I’m guessing I have some Septoria leaf spot or early blight (Alternaria) or Verticillium wilt happening, a bit of a misnomer as the disease doesn’t actually wilt tomatoes this early, typically, but causes bottom-upward leaf afflictions. I can live, and probably harvest some tomatoes, with either one of these, I suppose; I still have lots of leaves to do the job of photosynthesis, and maybe the weather will normalize now (whatever normal is anymore). Rutgers has a great PDF on fungal diseases of tomatoes, for your information.
Heirlooms (which are the plants in my garden that are being affected) are often not resistant to verticillium, though many modern hybrids have had resistance bred in (though resistance does not equal total immunity). I wrote about tomato troubles last year, when my biggest worry was that the fruits (below) just wouldn’t seem to ripen, and there are other links and tips there.
If you are seeing tomato troubles and feeling cheated, I hear you: Yes, I planted where there hadn’t been tomatoes lately (crop rotation), and took such care preparing the raised beds here for growing this year’s crop of tomatoes. I followed all my tomato-growing tips: The seed was started correctly; I spaced the transplants properly to allow for good air circulation, caged them right from the start to keep them up off the ground, and then it all just didn’t matter, did it?