Soil Parasite Costs Pacific Northwest Wheat Growers $51 Million in Lost Revenue

Transparent and thinner than a human hair, a parasitic roundworm is costing Pacific Northwest wheat growers $51 million in lost revenue each year because it’s cutting grain yields by an average of about 5 percent, according to Oregon State University researchers’ estimates.

Called the root-lesion nematode, it lives in the soil and feeds on the roots of wheat, oats and other crops. The challenge is that it isn’t easy to identify a nematode infestation as it can be confused with root rot, viruses or lack of nutrition because the effect on crops looks the same.

OSU plant pathologist Dr. Richard Smiley recommends if a growers suspects his fields are infested, submit soil samples to a nematode diagnostic lab and if results demonstrate a high density of the nematode.

Smiley: “There are a number of steps that can be taken. Crop rotation can, in some instances, reduce the density of the root lesion nematodes in the soil. Many of the agronomic crops that we produce in this region are good hosts for that nematode and allow it to multiply rapidly. But a few examples of hosts that do not allow the reproduction of the nematode are crops like safflower, flaxseed, spring peas and barley as well.”

Smiley adds one of the most effective tactics they've found is a three-year crop rotation where farmers skip two years between wheat plantings.