Potato Grower

44 POTATO GROWER | DECEMBER 2018 Nematode management primes potatoes for profit Deeper Look What a potato grower can't see at planting can be painfully visible at harvest. Nematodes cause the kind of pain that starts with reduced yield and tuber size. The damage can extend to bumps, warts and brown spots that diminish the potatoes' appearance and spread to the grower's profit potential. "Nematodes are ubiquitous, essentially," says Kelly Luff, a Bayer potato technical representative based in Idaho. "About 30 percent of the Snake River Plain potato acreage is infested with the root-knot species, and about 90 percent has lesion nematodes of one species or the other. A grower needs to keep an eye on his populations, take soil samples and keep them monitored. If nematodes aren't reduced, the populations can escalate until they are difficult to manage and it becomes unprofitable to raise a crop." Nematodes also open the door to disease, increasing the risk of early dying complex. "Early die is caused by a fungus called Verticillium dahliae," says Saad Hafez, a University of Idaho nematologist based at the Parma Research and Extension Center. "Root lesion nematodes facilitate disease development by feeding on potato roots and creating wounds where the fungus can enter. There is an interaction between lesion nematode and Verticillium wilt that causes early dying." Managing nematodes, then, not only can increase both quality and yield; it can also impact the cost of bringing the crop to harvest and decrease the risk of losing a field to disease. The first step is learning which nematodes are putting pressure on a field and at what levels. Growers generally sample in the fall. "Essentially, most acres have a nematode issue of one sort or the other. That doesn't mean the population meets the threshold for treatment, but it will be there," Luff says. Diggin' In NEMATODES| By Bayer CropScience Bayer potato specialist Kelly Luff investigates a field for nematode damage in southern Idaho.

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