It’s not difficult to spot some of the pests that plague West Virginia’s field crops. But others are more difficult to detect, and their effects are subtle and easily mistaken for other problems.

In 2009, the West Virginia Department of Agriculture (WVDA) will conduct the first-ever statewide survey for a variety of plant parasitic nematodes, microscopic worms that suck sap out of plant roots and can cause drops in crop yields as high as 80 percent if left untreated.

The survey is part of a national initiative that comes after the 2006 discovery of potato cyst nematode in Idaho and a 2007 discovery of a new species of corn cyst nematode in Tennessee.

The West Virginia survey will look for potato, corn and soybean nematodes.

“These are tricky organisms,” said WVDA Agricultural Plant Pathologist Norman Dart. “The crops may not show outward symptoms, but yields are reduced. Sometimes, you’ll see pockets of stunted plants. We’ll be paying special attention in those types of circumstances.”

The presence of nematodes can also affect international trade. Japan refused to take potatoes from the entire United States in 2006, even though the pest was found only in limited areas in Idaho.

One of the things that make nematodes so damaging is they can persist in soil for many years. The female worm can form cysts full of hundreds of eggs that can lay dormant, making the organisms very difficult to completely eradicate.

However, Dart said sanitation measures can be effective in preventing the spread of these pests.

“Nematodes can go anywhere the soil can take them,” he said. “Farmers should avoid buying used equipment from infested regions. They should take care to thoroughly wash any used equipment before bringing it to the farm and should be wary of nursery stock, which may carry infested dirt around the roots.”

Dart said West Virginia is thought to be free of serious nematodes, but the survey will be useful even if it merely confirms that belief. He added there is no cost to farmers for the survey, and that workers will get permission to take samples before entering private property.

Growers interested in participating in the survey should call 304-558-2212. More information is available at www.wvdaplantpath.com.