Farmers at the ready for new strain of basil fungus

06/24/2010 12:00 AM |

So far, no North Fork farmers have reported symptoms of downy mildew on their basil. Most are preparing for the worst but hoping for the best from this year’s crop.

“Eat your green vegetables!”

That simple sentence has become the refrain of the modern mother. But what should kids do when those leafy greens turn soggy yellow?

Researchers at Cornell’s Long Island Horticultural Research and Extension Center in Riverhead have identified a new strain of the fungus “downy mildew” that may threaten North Fork basil crops. Researchers are encouraging farmers and hobbyist gardeners to take early precautions to prevent the disease from spreading.

“Hopefully it’ll start to get progressively better as we have a better understanding of the disease and get better management in place,” said Meg McGrath, a Cornell researcher specializing in vegetable diseases. “Hopefully, commercial growers will get better fungicides to use. If commercial growers have better fungicides, then there will be fewer spores in the air to reach home gardeners.”

A basil-targeting variety of the microbe first appeared on Long Island in 2008, blown by the wind to farms across Long Island. This year, only one farm has reported symptoms of downy mildew on its basil, but Ms. McGrath expects the number of infected farms to jump in the coming months. The best way to fight it, she said, is to harvest basil plants as soon as they show signs of infection.

“You can cut basil at any point in time and still have a useful crop,” Ms. McGrath said. “So that’s one of my first and foremost recommendations to people. Watch it, and when it first starts, harvest your basil.”

Because the disease is not harmful to humans, people can still eat infected leaves if they are harvested soon enough. If allowed to worsen, however, infected basil plants develop yellow bands around the upper surface of the leaves with tiny specks of “downy” spores underneath, making the crop aesthetically unpalatable.

“It’s one of those diseases you can’t really avoid because the spores are so easily dispersed by the wind,” Ms. McGrath said. “But if it’s a really sunny, dry year, then there will be less of the disease compared to an overcast, rainy year.”

Ms. McGrath said bright and sunny days often provide the best defense against the disease’s fungal spores. The near-constant UV radiation effectively zaps airborne spores to death. On the other hand, if the sun doesn’t shine, the spores can spread like wildfire.

“Last year it was so wet, I couldn’t even get out to spray fungicides,” said Phil Schmitt, owner of Schmitt Farms in Riverhead. “You get foggy mornings and damp weather, that’s when you’re really going to see it.”

All types of fungi, whether good or bad, thrive in damp environments. Last year’s near-constant June rainfall, for instance, coincided with a record number of fungal diseases, nearly destroying some farmers’ crops.

Most farmers expect this year to be different.

“We haven’t had any problems yet,” said Eberhard Mueller, owner of Satur Farms in Cutchogue. “There were huge problems last year, but this year we’ve had pretty good growing conditions. Right now we have fairly dry weather, so I don’t see a problem in the future. So far, the growing season looks nice and promising.”

In the end, farmers are preparing for the worst but hoping things remain promising.

“If it happens, it happens,” said Bob Andrews, owner of Andrews Family Farm and Greenhouse in Wading River. “Up until now, everything looks good and clean. We just keep planting and harvesting.”

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