Insect-killing worms may save alfalfa

ByABC News
March 28, 2008, 12:08 PM

GREAT BEND, N.Y. -- Each spring, tens of millions of alfalfa snout beetles rise from the soil to continue their slow, methodical march across upstate New York, laying waste to fields of alfalfa in a single growing season.

Now, after 20 years of research, Cornell University scientists have discovered a pair of microscopic, insect-killing worms that prey on the beetle, an invasive species that has infested 500,000 acres in nine counties nearly 14% of the state's cropland since it was first identified in 1933.

Scientists hope the nematodes will be part of a two-pronged approach to thwart the wingless weevil. Cornell plant breeders also are working to develop a resistant variety of alfalfa.

"They've done the job," said John Peck, whose 200-year-old family farm in Jefferson County has been the site of Cornell's testing since 1991. "I went from a heavily infested soil to virtually nothing."

The adult beetles surface in May after laying eggs at the root of the alfalfa plant. The emerging larvae then feed on plant roots.

"With the discovery of these two nematodes, it's a big deal," said Robert Mungari, director of the Division of Plant Industry at the state Department of Agriculture and Markets. "It will make a significant impact on the ability of growers to deal with this persistent pest."

In 2006, New York farmers harvested 370,000 acres of alfalfa worth nearly $112.7 million, making it the state's third most valuable crop behind corn and hay. But alfalfa also is vital to the state's $1.5 billion dairy industry.

Most of the state's 6,000 dairy farmers grow their own alfalfa, said Peter Gregg, a spokesman for the New York Farm Bureau. If a farmer had to find another feed for cows, it would likely be soybeans, currently at record prices, he said.

"Certainly for farmers who have experienced an infestation, it has been devastating," Gregg said.

The alfalfa snout beetle was first reported in North America in 1896 in Oswego, likely deposited from ship ballast. Farmers first reported it as a pest in 1933, about a decade after alfalfa was planted as a forage crop in New York.