Tomatoes and the Lingering Terror of Late Blight

By Nicole Sugerman

Tomatoes are in! I am excited after a spring in which I did not allow myself to think about how much I enjoy this beloved summer crop. I did not think about their juiciness, or imagine all the recipes I could make that feature this joyful fruit. On Monday, we had our first gigantic tomato harvest of the season—once they come in, they really come in—and I allowed myself to feel excitement over eating tomatoes for a long time to come, but also relief; we got tomatoes before late blight got us.

Those of you who are returning members may remember last year’s late blight. Brought in on seedlings sold at big-box stores from commercial greenhouses in the south, where late blight can overwinter, late blight devastated the tomato and potato crops of farmers throughout the northeastern United States. Late blight is named for the fact that it usually hits this region late in the season, traveling up from the south and thriving on cooler weather, but last year’s unusually cool wet conditions combined with its assisted travel to this area early in the season created the perfect conditions to foster a minor catastrophe. Many small farms make up to 30% of their income on tomatoes. While some farmers, like us, were able to keep their tomatoes alive and producing (with diminished yields and quality, in many cases including ours) for a while, some farms lost their entire crop before a single tomato ripened. I recently spoke to one farmer who operates a fifteen acre organic farm in New Jersey who estimates that he lost $30,000 worth of tomatoes last season; the tomatoes were all staked, tied, pruned, and ready, before late blight wiped out his entire crop.

We are all still a little traumatized. We still swap late blight stories, and strategize and debate about whether we will get it this year, and how we might avoid it; even though the weather is hot and dry, and the late blight was not supposed to be able to overwinter in this area, the late blight is still returning earlier than usual, with sightings already reported in western Pennsylvania, Maryland, and Connecticut. One farmer I know is letting all the weeds get big between his tomato rows to try to decrease air space for spore travel, which is how late blight spreads. Other farmers I know are spraying copper sulfate, an organic-approved fungicide, preemptively. Others are just stocking up on fancier, more efficient spray equipment so they can be ready if the late blight hits.

We had a late blight scare already this season. On our lowest row of tomatoes, we noticed spots that resembled the late blight lesions of last season. We concluded that we had the disease. Nina and I stayed at the farm until ten o’clock that Friday night, removing affected leaves from the plants and spraying copper to try to prevent it from spreading. We took samples of the leaves to send to Penn State Extension, which performs free diagnostic tests on plant samples sent to them by farmers, just to make sure, but we were sure our tomatoes were doomed for another season.

Luckily, we had misdiagnosed our tomato disease. Two days after we sent in the samples, I got a call from Penn State assuring me that the samples were late blight free—we had early blight, a common, not-very threatening early season disease for organic growers, and Septoria, a leaf spot-causing fungus. Both diseases can be controlled through crop rotation, increased air circulation, and cleaning up crop debris in the fall to prevent overwintering. While having disease is not good news, tomatoes, especially heirlooms, catch diseases very easily, so getting them is not particularly worrisome if they are not late blight! We were thrilled and relieved.

I have heard other farmers tell me the same story, with false scares and anxious tomato patrolling throughout the spring. While we could still get late blight, at least the tomatoes are in and producing heavily—so we can all enjoy the amazing taste of tomatoes for what I hope will be a long while. Even though harvesting tomatoes is no one’s favorite task on the farm (it takes forever, the fruits damage easily, and the plants make us itch!) we are all thankful for the privilege this year. Enjoy your tomatoes! We are happy to have them for you.