Late blight, a plant disease that can devastate tomato and potato crops, will end up costing Kellner’s BackAcre Garden $20,000, one of the owners of the Denmark commercial growing operation said. The disease made an appearance this week in two places on opposite ends of Brown County, causing UW-Extension horticulturist Vijai Pandian to sound the alarm. “Gardeners need to check for symptoms,” Pandian said Wednesday. “This isn’t just a gardener’s problem, it’s a community problem.” The disease started with two plants on Kellner’s BackAcre Garden in Denmark late last week and, in just a matter of days, wiped out most of Kellner’s 2,200 remaining tomato plants, said Nancy Kellner, co-owner of the organic garden. Late blight is a fast-moving plant disease spread by spores that can be carried in the air or transferred by contact. Aside from the operation’s initial investment in the plants, which crews start from seed indoors in the spring, the garden will lose money from loss of income, Kellner said. “My husband estimates an impact of about $10 a plant,” she said. And the Kellners need help gathering up all the diseased plants. A crew of three people spent hours working Tuesday night, but the three large piles of dead plants and diseased fruit they gathered represent just a tiny percentage of the huge field of blighted plants the Kellners need to take care of before the next rainstorm spreads the late blight spores even further. The strategy is to get the plants and fruit into piles, cover them with tarps and let the sun beat down on them, baking them and killing the spores. Only then is the stuff safe for burning or burying, Pandian said. Composting is not an option, because the spores will thrive and spread, he said. At the extreme opposite corner of Brown County, in the town of Pittsfield, the same disease wiped out 18 tomato plants in a garden shared by property owner Jack Kraszewski and his brother-in-law, Dan Hoffman of Green Bay. Hoffman had just thinned the lush, bountiful tomato crop days ago and returned this weekend to find all 18 plants dead and the tomatoes blackened, cracked and oozing. “I salvaged none of them,” Hoffman said. “Everything was dead. Completely.” Late blight is the same disease that caused the great potato famine in Ireland in the middle of the 19th century. It’s an aggressive airborne disease that can affect every plant related to the tomato, including potatoes, egg plants and peppers, Pandian said. Tomatoes and potatoes are especially susceptible, though no sign has shown up in area potatoes, he said. Late blight first shows up as white spores on the underside of leaves. Soon after, the leaf will turn brown, then black, and with days the plant itself will collapse and turn black. The tomatoes turn chocolate brown, split open and turn black. Once it is identified in an area, gardeners within a 25-mile radius need to be on high alert to protect their plants and prevent spreading the disease, Pandian said. Hoffman’s potatoes did poorly this summer but seemed to be unaffected by the late blight. But the disease took out his tomato plants in a matter of a few days. His and the Kellners' were the only two reports of the blight in Brown County this summer, but Pandian suspects there have been — and will be — many more plants affected by the disease. “Many gardeners only notice it at the very late stage, when the plant is collapsing, turning black,” Pandian said. “By that time, it’s too late. Gardeners need to check their tomatoes every day to see if there’s any sign of infection.” Spraying the plants regularly with copper-based fungicide or chlorothalonil can prevent the disease. Pandian also recommends avoiding overhead irrigation and watering the plants at the base, instead, to avoid infecting them to begin with. When the disease shows up, preventing spread is crucial, Pandian said. Don’t let the plants remain there, and don’t compost them. Put the plants and tomatoes in a black plastic garbage bag, seal it and leave it in the hot sun for at least a week, Pandian said. The spores that spread the disease will get cooked out. The plants and fruits can then be buried, burned or sent to a landfill, he said. Anyone who suspects their plants are infected can bring a sample to the UW-Extension office, 1150 Bellevue St., during regular business hours for a free diagnosis. Pandian recommended against eating the fruit if the plant shows any sign of the blight. “Usually the infected fruit has broken skin, and that can harbor pathogens,” he said. The first report of the blight this year was on June 23, in Adams County. Later reports came from Waushara, Wood, Marquette, Portage, Columbia, Fond du Lac, Polk, St. Croix , Marathon, Walworth and Kenosha counties. Brown County has had reported outbreaks every year since 2010 except last year, although Pandian says it likely happened then, too, but wasn’t reported. Source - http://www.greenbaypressgazette.com