Irene brings another unwelcome passenger…Late Blight

I’m not a gardener but when I presented the information to Martha yesterday that Late Blight had returned to the North Country, she was somewhat aghast. After reading about it I can see why.

Late Blight decimated North Country tomato crops a few years ago, and this year, Irene brought the fungal infection’s spores up the coast. Now they’re affecting tomato and potato plants. Cornell cooperative extension in St. Lawrence County has confirmed cases, and Jefferson county’s awaiting results, as reported in the Watertown Daily Times.

Early signs of infection on tomatoes are brown spots on stems that quickly grow…with white fungal growth developing under moist conditions, that leads to soft rot collapsing the stem.

The most visible symptoms are nickel-sized or larger olive green to brown spots on leaves, and slightly fuzzy white fungal growth on the underside.

The Cooperative Extension is advising gardeners to harvest what’s left of their tomato crop—even if some fruits aren’t yet ripe.

And if you see signs of infection on tomatoes, the extension told north country now that vines should be either piled and securely covered with a tarp—in a sunny area—or bagged and sealed until all green plant material has blackened. You shouldn’t compost infected plants.

Affected potato plants should be cut off at the base, and treated like tomato plants. The potatoes can be left a week or two to harden up and then harvested as usual—although you should take extra care not to damage them.

A really excellent primer on Late Blight is here–along with much more detailed instructions on what to do about it–from Cornell Cooperative Extension. Good luck with this one–it’s nasty.

Tags: , ,

8 Comments on “Irene brings another unwelcome passenger…Late Blight”

Leave a Comment
  1. tootightmike says:

    At least this year it had the decency to come late. It IS mid-September, so we’re kind of on borrowed time here.

  2. knuckleheadedliberal says:

    To reiterate what ttmike said, before global warming, chances were that we would already have had a frost by now or maybe in a week.

    Pick’em while you got’em.

  3. Sarah Prince says:

    In the Ausable East Branch valley, there are a lot of flood-contaminated tomatoes just lying around being ugly….

  4. Peter Hahn says:

    This is the disease that caused the Irish Potato famine. Seems to me you want to make sure no diseased material is still around to start the cycle early in your farm/garden next year. Potato culls are a source.

  5. Paul says:

    “To reiterate what ttmike said, before global warming, chances were that we would already have had a frost by now or maybe in a week.”

    This makes no sense. What are you talking about? Global warming has delayed the arrival of frost in many areas? Is there any evidence of this? Or is this the usual “blame everything” on global warming?

    You may be right but this is the first I have heard this one. Can you point us to some data?

    Also many areas have already had a frost or will be having one just about right on schedule, or even a bit early this year.

  6. knuckleheadedliberal says:

    Paul, as a long time gardener I can tell you from my experience that the first fall frost in my area is getting later. Not scientific but true none-the-less. I used to get a first frost in early to mid September and now I can count on first frost somewhere between mid September and mid-to-late October. I picked eggplant on October 19th a couple years ago!!!! Haven’t had a frost yet this year. Maybe tonight but I haven’t even bothered to cover anything because I don’t believe it. Last night I had 34 degrees–not close enough for horse shoes. I’ll let you know if I was wrong tomorrow.

    I’ll have to dig out my county Water and Soil Conservation District book to check the actual statistics, if I can find it, but meanwhile you can check this website which shows an August 28 date to expect frost in Lake Placid. Have they had a frost yet?

  7. knuckleheadedliberal says:

    Oops forgot the website:

  8. knuckleheadedliberal says:

    No frost last night for me.

    I dug out my county soil survey book, issued January 1989. It gives this info on first fall frost recorded from 1951-76:

    Temp. 32 or lower
    1 year in 10 earlier than Sept. 19
    2 years in 10 earlier than Sept. 23
    5 years in 10 earlier than Sept. 29

    For the last 3 years in a row I haven’t seen 32 degrees before early to mid October. I know I’m not likely to convince you, Paul, but my tomato and basil plants and the ragweed all seem pretty convinced it is getting warmer.

Leave a Reply