As if tomato growers didn't have enough to worry about with the constant rain and scarce sunshine, now tomato plants across New England have become infected with late blight. That's the same deadly fungal disease that caused the Irish potato famine in the 1840s.
The disease, which usually isn't a problem until late August, was first detected in New York about three weeks ago, according to Dr. Cheryl A. Smith, a plant health specialist for the University of New Hampshire Cooperative Extension. The disease spread to all six New England states within a week.
"The weather we've been having is very, very favorable for the development of the disease, and it moves quick," Smith said.
The last time late blight hit New England was almost 10 years ago — and it hit hard. One tomato grower lost a 5-acre field of tomato plants in just six days, Smith said.
Meg McGrath, a professor of plant pathology at Cornell University, said late blight is "worse than the bubonic plague for plants."
"People need to realize this is probably one of the worst diseases we have in the vegetable world," she said. "It's certain death for a tomato plant."
The owners of Peters Farm in Salem hope to avoid a tomato disaster. But Mike Peters said he fears some of the farm's 3,000 tomato plants have become infected with the disease.
"It looks like some sort of disease is on a lot of our plants at this time and it definitely looks like a blight," co-owner Mike Peters said yesterday.
"It's a small percentage at this time, but we're worried about it spreading."
Peters and other farmers also have to worry about not being able to spray fungicides, the only way to prevent blight, because of the wet weather.
"You want to make sure that fungicide is down prior to your weather problems and, if you have a heavy rain, then you have to reapply," said Scott Johnson, owner of Highland View Farms in Windham.
Johnson, who hasn't lost any tomato plants yet this season, said he's being cautious after losing some of last year's tomato plants to the deadly disease.
"We had a wet year last year and our tomatoes just died — with fungus," he said. "Once you see it, you're done."
Johnson said the weather this month will be critical in determining whether he loses another year's tomato plants.
Late blight, which is characterized by brown spots on the leaves and fruit, can spread in two ways.
It can become airborne and blow up to several miles away, or it can spread through physical contact with infected plant material, which is what happened this year.
The New Hampshire Department of Agriculture has pinpointed major Alabama grower Bonnie Plants as the source of infected tomato plants distributed to big-box stores such as The Home Depot, Lowe's, Wal-Mart and Kmart, according to state entomologist Tom Durkis.
The Home Depot has already removed the infected plants from all 20 of their New Hampshire stores.
"All the plants were removed immediately when they figured out what was going on," The Home Depot spokeswoman Jen King said. "We want to take care of our customers and we'll be working with them to offer a full refund or exchange."
Infected plants also were removed from Wal-Mart stores in the Northeast, spokeswoman Caren Epstein said.
Now that the plants have been removed from retail store shelves, the next step is informing consumers who may have purchased the infected plants for their home gardens.
"Once the plants are infected, the best thing a home gardener can do is bag that plant up and put it in the garbage — no composting," Smith said.
Tomato plants that haven't been infected can be protected by using a fungicide with the active ingredient chlorothalonil, Smith said.
It is too early in the season to know whether infected plants will taint large crops or negatively affect commercial growers. But if that happens, growers could be forced to raise prices to cover costs associated with combating the disease.
Material from The Associated Press was used in this report.
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