Sunday, August 9, 2009

more on late blight and tomatoes

At a birthday party for my daughter this evening, I was talking to one of my neighbors. "You have to come over and look at one of my tomato plants," he said. "Something's up." He said the bottom leaves were beginning to shrivel. Could be some kind of run-of-the-mill wilt, but of course I thought it could also be Late Blight, the tomato disease of 2009. My neighbor's news felt especially bad, because I've started to notice some shriveling on one of my plants, and it's spreading at an alarming rate.

We're hobby gardeners, and I have come to accept that tomato plants are going to get hit with one thing or another by the end of the year. They don't live forever. But this year has been especially bad for tomato growers. Is there a lesson that we can learn from the Phytophthora infestans plague of 2009?

Here's one: Consolidation of agriculture in the United States is not just a problem of Big Ag and far-off farmers. It spreads to all of us.

Let me explain: The tomato (and potato) disease of 2009 came from concentrated, factory-farm-style nurseries that supply Big Box retailers, which then spread to the home gardener. This was explained well in a story today in The New York Times:

According to plant pathologists, this killer round of blight began with a widespread infiltration of the disease in tomato starter plants. Large retailers like Home Depot, Kmart, Lowe’s and Wal-Mart bought starter plants from industrial breeding operations in the South and distributed them throughout the Northeast. (Fungal spores, which can travel up to 40 miles, may also have been dispersed in transit.) Once those infected starter plants arrived at the stores, they were purchased and planted, transferring their pathogens like tiny Trojan horses into backyard and community gardens. Perhaps this is why the Northeast was hit so viciously: instead of being spread through large farms, the blight sneaked through lots of little gardens, enabling it to escape the attention of the people who track plant diseases.

The author of this essay, Dan Barber, at times seems on the verge of blaming the amateur home gardener for this problem. ("Here’s the unhappy twist: the explosion of home gardeners -- the very people most conscious of buying local food and opting out of the conventional food chain -- has paradoxically set the stage for the worst local tomato harvest in memory.") But he eventually acknowledges the real problem: a super-concentrated agricultural system that gets its supplies from mega-growers is not very resilient. Disease spreads quickly through these systems, as it would through any monoculture.

For the most part, Joe and I didn't get our plants from nurseries. We grew them from seed, starting indoors in the early spring, and we planted a bunch of different varieties (more variety means more genetic diversity, and maybe more disease resistance). For those reasons, our tomatoes have fared pretty well this year, while some of our neighbors' plants have completely wilted, as if doused in rubbing alcohol and lit on fire.

We have yet to see whether we'll make it to the end of the season disease-free. But one thing is certain: We will again be growing from seed next year, and growing many different kinds of tomatoes.

--Scott Carlson

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