US: Late blight hit tomato growers in North Carolina

Late blight has been confirmed in tomatoes in Guilford County — the first time it has ever been recorded this early in the season, according to the Guilford County Cooperative Extension office. The fungus-like pathogen typically affects mountainous counties in North Carolina because it needs wet and humid weather to thrive.

But the 12.5 inches of rain in the Piedmont since June 1, according to data from the National Weather Service, are more than double the normal value for that period and have created ideal conditions for plant diseases like late blight.

“A dry year will hurt you and make you work more. A wet year will put you out of business,” said George Smith, co-owner of Smith Farms & Greenhouses in Gibsonville. “There’s nothing you can do to take the water away.”

Smith said he’s certain he’s seen late blight on his plants, though he hasn’t had it tested and confirmed. The disease can cause tomatoes to rot. Symptoms include lesions that change the shape of leaves, and sometimes fuzzy growth on the lesions.

But the blight is just one problem of many, he said. The wet weather has contributed to several diseases on his farm.

Heirloom tomatoes are popular among home gardeners, but are one of the least resistant to late blight, N.C. A&T horticultural specialist Sanjun Gu said.

Gardeners might try planting heirlooms along with hybrid tomatoes, which are much more resistant to late blight, Gu said.

“Hybrids grow much more vigorously,” Gu said. “With more variety, the chances for all of them to get the disease are much lower.”

Pruning also increases airflow and lessens chances for tomatoes to become infected, Gu said.

Gardeners can reduce the risk of disease by not planting tomatoes in the same place they have for the last three to five years, Gu said.

Smith sells more transplants than he does actual tomatoes, most of which are grown in greenhouses. He normally doesn’t spray his transplants until they’re about two months old, but he’s been spraying them as young as 10 days old because conditions are so wet.

Fungicides prevent late blight, but do not cure an infected plant. This poses a particular challenge for organic farms.

“Late blight is a death sentence for the tomatoes,” Smith said. “It’s just how long and how much you can salvage ... before it kills it off.”

Source: www.news-record.com