Late blight strikes local tomato crop

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By Christopher Brooke, Reporter

Tomato plants with a fungal disease that's ravaging gardens this year need to be disposed of properly, lest they damage next year's crop, Virginia Cooperative Extension agents warn.

Gardens in the Twin Counties and throughout the East have experienced a "tremendous loss" of garden tomatoes due to late blight, said Extension agent Kevin Spurlin.

"Unfortunately, the disease is quite devastating with complete crop losses common," he said. "There are measures that home gardeners need to take soon to limit the infection potential next year."

If the disease strikes a garden, it can strike fast, said Extension agent Wythe Morris.

He worked with a gardener from Wythe County who grew 47 varieties of heirloom tomatoes. They went from making good progress to a rapid decline.

"It looked like somebody went over them with a blowtorch," Morris said.

Spurlin visited a garden in Galax that had 20 tomato plants loaded with fruit that were killed by the disease.

The disease had struck most gardens in the area. "Tomatoes are going to be a losing proposition this year."

The disease causes severe leaf wilting and stem lesions on tomato and potato plants, according to information from Extension. It also causes large and rapidly rotting lesions on the tomato and potatoes themselves.

Some preventative measures can control the fungus, Spurlin said. "It's not hard to kill if you know ahead of time. We don't see it that often so we weren't prepared."

The wet and mild weather conditions have resulted in the vigorous spread of the disease. Morris said the first reports of late blight came from the New York and Pennsylvania areas and it's continued its destruction down the Atlantic coast.

Reports indicated that some infected plants had made it to big box stores in the Northeast, he said.

"A wet, cool spring followed by an unusually mild summer and then recent humid conditions of cool nights and warm days have provided ideal conditions for late blight," the Extension information states.

Though problems have been widespread for home gardens, Morris said commercial growers have not been affected.

"Most of your commercial growers have adopted a preventative spray type program," he said.

Because of how rapidly it causes damage, by the time a gardener finds late blight on plants, it's already too late.

Extension agents say that gardeners who spot the blight should take precautions from incubating the disease to keep it from rearing up among next year's plantings.

Damaged plant material can harbor the fungus and needs to be removed from the garden.

"You can throw this material in the trash, put it on a brush pile to burn or bury it two feet underground," Extension states. "Fortunately, late blight will not overwinter in the soil alone. It must be in living tissue such as old, infected tomatoes or potatoes."

Be wary of volunteer plants, the agency's warning says. Do not put the diseased material in a compost pile or the virus may persist until next season.

"If you are careful to eliminate this year's diseased plants, and weather conditions next summer are hotter and drier, the likelihood of a repeat will be less."

Chlorothalonil, which can be found in most garden centers, can be used as a preventative spray, Extension officials say.

The disease outbreak has some gardeners thinking about planting a few tomatoes with some resistance next year, along with their heirlooms, Morris said. "You need to have a back-up plan."