Farms Wet for Weeks Causes Worsened Tomato Blight


Culture Staff Writer | Grace Hermanns |

The excessive wet weather during the months of June and July had pronounced effects on tomato crops for the rest of this past summer season. Tomato plants usually need about six to eight hours of sunlight per day, allowing the sun to dry off any rain on the plants before nightfall.  But with precipitation far surpassing the monthly averages for June and July, tomato crops, especially organic crops that receive no fungicide or herbicide treatment, were hit harder with diseases such as early and late blight.

Yellowed leaves and black spots characterize early blight, a disease caused by the fungus alternaria solani, which spreads easily with moisture. According to Weather Underground, it rained more than 13 inches during June and July in Athens, Ohio, which kept fields under water to the point where tomato farmers and gardeners could not step foot in their fields for days. WeatherDB, a weather research website, said the average precipitations for those two summer months in Athens, Ohio is little over 10 inches.

Ronda Clark of Blackberry Sage Farm near Amesville, a farm that sells produce at the Athens Farmer’s Market, said, “I lost a lot of production. I did twice as much work to get half as much produce. I put in probably 350 tomato plants, and I have a production of about 150.” Clark does not use sprays of any kind, and although she has come to expect seeing blight on some of her plants each harvest season, the work was especially hard for her this summer. Her sales have been lower than normal, which she partly attributed to the weather. “Everybody is losing money this year. Anything is a significant loss when you’re a farmer.”

Ed Perkins of Sassafras Farms in New Marshfield, another farm that sells fresh produce at the farmer’s market, spoke similarly about his tomato plants. “I fought with early blight,” he said while scurrying around his vendor booth. “It killed off my first crop, which normally doesn’t happen, and the next crop just isn’t producing like it should be. And I can’t figure out why.”

The disease can occur over a wide range of climatic conditions, according to the Ohio State University Cooperative Extension fact sheet on tomato blight. The extreme wet weather followed by a small dry period in early August provided prime conditions for the disease.

Judy Jenkinson saved some of her heirloom tomato plants, but the rest were pulled out of the ground when the summer rains caused blight, resulting in these black lesions. Source: Grace Hermanns
Judy Jenkinson saved some of her heirloom tomato plants, but the rest were pulled out of the ground when the summer rains caused blight, resulting in these black lesions. Source: Grace Hermanns

When blight appears, it is imperative to remove the infected leaves and not to let them fall to the soil, where the spores can then spread to other plants nearby. The yellowing will slowly make its way up the plant to the fruits, where it causes black lesions. The leaves and plants cannot be composted. With the soil being constantly soaked over a two-month period, the spores had no trouble spreading when infected leaves were splashed with falling raindrops. Tomato plants can make it through blight only if the disease is caught early on. But, with what seemed to be never-ending rain and thunderstorms, it proved hard for some farmers to catch and rid their plants of blight.

The heirloom tomatoes at Duff Farms in Dexter, Ohio, had to be completely taken out of the ground because Robin Duff saw yellowed leaves and black spots on almost all of them. Normally, the seeds from heirloom tomatoes can be kept and planted again, ensuring that the next crop has the same traits as the tomato from which the seed was harvested. Duff, however, will have to buy new heirloom seeds because her first crop had blight.

Some of these herbicide-free farmers have differing beliefs than those farmers who utilize herbicides. Farms such as Witten Farm in Lowell, Ohio, which plants 90,000 tomato plants in three summer rotations, can’t afford to lose that crop to disease. Even with sprays to prevent diseases and hybrid tomatoes bred to avoid diseases, the tomato yield per acre has been gradually decreasing. The United States Department of Agriculture showed the Ohio acreage yields for tomatoes in the open fresh market as decreasing in production; in 2010, only 2,900 acres were harvested, but each acre yielded an average of 27,000 pounds. In 2013, 3,400 acres were harvested, but each acre only yielded an average of 17,500 pounds.

Mitch Meadows of Mitch’s Produce & Greenhouse in Middleport, Ohio, elaborated on his production. “We have to use fungicides and herbicides otherwise we wouldn’t have this business. We’ve planted more rounds of tomatoes and they’re producing great. I wouldn’t say our production has been the same as last year, but our plants haven’t been decimated.”

Jenkinson Farm and Gardens is another vendor of produce at the farmers market and elects to forgo the herbicides in exchange for more natural produce. “I’m doing my part for the Earth by letting my vegetables be,” Judy Jenkinson said at her farm in Albany, “I had one guy complain about bugs in his raspberries, and he suggested I spray them three times a week. I told him I’d rather have the bugs.” Much like other organic farmers this harvest season, she pulled out many of her first plants because of the rain and diseases. She did not let the tomatoes go to waste though; she carved out the black spots and fed her chickens with the untouched parts of the fruit.

Spraying with herbicides or growing hybrid tomatoes isn’t the only way to prevent fungal diseases. Arnold Farms in McConnelsville uses high tunnels to control how much water hits the tomato plants. David Marrison, a master gardener volunteer for the Ohio State University Cooperative Extension program, suggested layering the soil with mulch to prevent splash of inoculum from the soil and regularly rotating crops each season.

High tunnels and greenhouses are effective proactive measures to take against over-saturating rains and tomato diseases, but not all farmers can afford such things, nor do their smaller farms provide adequate space. “I would love to have a greenhouse, but I don’t have the location for it,” said Clark. “It was a very, very hard year. And, I’m hoping it’s an incident, and not global warming. But I’m hoping it gets better.”