The summer’s wet, cool weather is making life difficult for Pennsylvania’s tomato farmers.
The Penn State Extension, which monitors agricultural phenomenon, has confirmed fungal outbreaks in 13 counties from Lackawanna County to as far west as Cambria County.
The spreading fungus is known as “late blight” and is one of the worst threats tomato growers face, according to Beth Gugino, a plant pathologist for the Penn State Extension.
“It’s particularly devastating because it can wipe out a crop or a homeowners tomatoes or potatoes in a matter of a few days,” Gugino said. “I’ve seen entire fields be wiped out in as few as six or seven days.”
The fungus is spread by spores, often carried more than 50 miles by wind, according to Philip Bauerle of the Allegheny County Branch of the Penn State Extension. It causes dark green-grey wet spots on tomato or potato leaves, which then enlarge and turn dark brown. Infected plants die in less than five days.
Gugino says the amount of blight seen in PA so far is not too different from previous years, but the rainy weather has made the spread slightly worse.
Rob Shenot manages Shenot Farm in Wexford, and says that he has not seen any signs of late blight so far. He explained how heavy rains can make late blight worse.
“If you have spores at the top of the plant, and you have a heavy rain, it’s very easy for those spores to wash down and spread throughout the plant very quickly,” Shenot said.
According to Shenot, his farm has experienced a few outbreaks of early blight, a less serious and more common infection. Early blight, unlike its more aggressive cousin, still allows fruit to be harvested from infected plants. According to Shenot, late blight is much more intimidating, partially because it gives farmers very few options.
“If you already have it, you know, you can spray a lot of fungicides and things like that, but if it’s already infected in your plant, chances are it’s too late,” Shenot said.
Infected crops are often burned to prevent further spread, and some farms, like Shenot’s, use drip irrigation systems that avoid watering plants from above. Shenot said that in the event of an infection, his pickers and other farm workers are careful not to carry spores from diseased fields to clean fields on their clothes or skin.
Gugino says she does not see the spread of late blight slowing any time soon.
“I anticipate that we’re going to continue to get additional reports of late blight statewide. Again, the cooler temperatures that we’ve been having, especially in the evening. The disease doesn’t stop progressing at night,” Gugino said.
Both Bauerle and Shenot pointed out that, while late blight is a serious problem, Allegheny County tomato farmers and gardeners have other worries right now. The cool weather means fruit is remaining green for longer than usual. The extra moisture is causing several fruit to fill with excess water and split.
Bauerle said, among other consequences, this means the annual Garden in the Parks event on Aug. 16th hosted by the Penn State Master Gardeners might not feature its traditional tomato-tasting.