Relatively new fungus takes toll on basil crop
DES MOINES, Iowa — A fungus spreading among the nation's basil crop might leave lovers of Italian and Thai food feeling a bit bland.
Basil downy mildew first surfaced in the U.S. around 2007 and is slowly but surely ruining the herb at spots across the country. Hardest hit areas are on the East Coast, but it also has been found as far west as California.
For growers, the fungus can be devastating.
"We destroyed all our crop this year," said Francesco DeBaggio of DeBaggio's Herb Farm in Chantilly, Va. "We killed about 6,000 plants, or about $18,000 worth of plants."
DeBaggio said he first noticed it in May and didn't realize what it was. Once he determined it was downy mildew he decided to destroy his crop.
"It's huge for us," he said. "We're small, so it's fairly significant. We would have sold 100 percent of those that were destroyed."
Basil is commonly used to make pesto and tomato sauce and is a popular ingredient in Italian and Thai recipes. It's also often used in salads or sprinkled on tomatoes.
Margaret McGrath, an associate professor of plant pathology at Cornell University, said the fungus is likely more of a problem for home gardeners and herb farmers who might not have access to fungicides that are available to larger commercial growers.
"We think it's moving around each year, surviving over the winter and then moving north during the summer," McGrath said.
The relatively recent emergence of the fungus means many growers don't know about it, McGrath said.
In some cases, growers might think the yellowing leaves indicate the plant needs more fertilizer.
"And that's not going to help at all," McGrath said.
She said areas of shade and high humidity seem to be more susceptible to the fungus and gardeners can help control it by spacing the plants farther apart and planting them in areas that get more sun.
It is carried by spores that travel through the air, which means "it has the potential to go almost anywhere," McGrath said.
The spores are a gray or purplish color. Affected leaves begin to yellow but quickly turn brown before they die, McGrath said.
Downy mildew fungi have been around for years, with different forms affecting different plants and vegetables, but the downy mildew affecting basil is new, McGrath said.
It takes about two weeks from the time the plant is infected to when the fungus first appears, and DeBaggio said that means some growers might be selling infected plants without knowing it.
Margie Pikarsky, owner of the organic Bee Heaven Farm in Redland, Fla., said she has had problems growing basil since 2008. Until she recently heard of the fungus, she didn't know it was to blame for her failed crop.
At first she and other farmers thought there was a problem with the seed. The next year she blamed cold weather. She switched seed sources and the weather warmed, but the herb still would not grow.
The fungus, which poses no risk to human health, could have the biggest impact on the market for fresh cut basil.
So far, McGrath said the problem isn't so bad that it has cut into supplies or caused prices to rise.
George Ball, chief executive officer of Warminster, Pa.-based Burpee Seeds, said it's important for people to realize the blight is manageable if precautions are taken, such as spreading plants out and putting them in sunnier locations.
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