For vegetable lovers in New Hampshire and Vermont, there’s a nightmare scenario making the rounds right now. It goes something like this.
Last spring, somewhere in the twin states, someone planted a garden for the first time. Perhaps prompted by high food prices, or the latest food-contamination scare, or maybe just a desire to spend more time in the fresh air, this person turned up a corner of the yard and planted some old favorites: peas, say, and potatoes and tomatoes. And some greens for good measure. So far, so good.
But then the Promising Spring of 2009 turned into the Lost Summer of 2009. It started raining in May and kept at it until August. It was chilly. Cold, even. The garden did poorly. And then things really went downhill: late blight struck, wiping out the tomatoes and spuds altogether. Our budding home gardener threw in the towel in disgust, walked away from gardening and vowed never to set foot on that cursed patch of ground again.
Before we cut to the final scene of this horror movie, a word about late blight. Many readers are no doubt aware of last summer’s late-blight infestation, in which a fungus, Phytopthera infestans, decimated local tomato and potato plantings. The fungus over-winters in southeastern United States but does not generally over-winter in New England due to the cold temperatures. Instead, the fungus typically works its way northward on summer weather fronts, perhaps arriving in New England, if at all, late in the growing season, after the bulk of the harvest is already assured. Hence the common name, ‘late blight.’
Last summer, however, a large nursery in Alabama provided (inadvertently, we assume) blight-infested tomato seedlings to large retailers across the Northeast, which promptly sold them to home gardeners in May and June. By the end of June, the blight, having effectively hitch-hiked north three months early, began its devastation.
But that’s ancient history, right? Didn’t winter reset the clock?
Maybe not. Late blight does not generally overwinter in northern New England, but it can if it finds a place to snuggle underground on some live host tissue. Tomatoes are not a concern because this past winter, though warm, was more than cold enough to freeze and kill every tomato plant in the region (and the blight cannot survive on tomatoes seeds.) But potatoes are another story. Spuds underground that don’t freeze are very much alive.
Back to the horror movie, already in progress. Our home gardener, abandoning the ravaged garden last July, left the half-dozen, blight-decimated potato plants in the ground. The foliage was shriveled, and the tiny potatoes were not worth the effort to harvest. There the spuds sat all winter, six inches underground, easily surviving what turned out to be a mild winter. So about now, in mid- to late-April, those spuds are ready to sprout, sending green shoots (and fresh Phytopthera spores) up into the Promising Spring of 2010.
Cue the scary music from Poltergeist: “They’re BA-ACK!”
To prevent this horrible re-run, there are a few simple steps we all need to take. First and foremost, if you happen to be that demoralized home gardener, or if you know the person who is, please spread the word that all those potatoes from 2009 must be dug up and disposed of as soon as possible. Every tuber from 2009 is considered suspect: double bag them and take them to the dump. Don’t wait for them to sprout. And then keep an eye out for any spud that escaped your notice the first time around.
Step two is to buy new seed potatoes that aren’t infected with late blight. Reputable seed sellers can certify that their tubers are blight free; if you’re in the habit of re-planting seed potatoes from your own stock, think seriously about not doing so this year. Make sure you know what late blight looks like in infected seed stock if you insist on proceeding.
When it comes to buying tomato seedlings, the source of this whole disaster a year ago, make sure you aren’t buying infected plants. Anything from a local greenhouse or nursery should be fine, since the fungus can’t survive on seeds or in potting soil. If you’d prefer to buy your plants from a larger retailer that trucks the plants from down south, ask to see the paperwork that verifies that the tomatoes are blight-free. If they can’t produce the paperwork, don’t buy the plants.
If we can get through 2010 without a major outbreak, we should be back in the clear. If not, we’re going to end up with front-row seats to reruns of the old horror movie. On the bright side, we’ll have plenty of rotten tomatoes to throw at the screen.