Despite their microscopic size, Columbia root-knot nematodes (CRN) have potential to inflict huge losses—about $40 million annually—by tunneling into potatoes to feed. But this level of loss isn’t likely to happen, thanks to fumigants growers now use—at a cost of $20 million annually.
In seeking alternatives to using chemical fumigants, ARS and collaborating scientists are field-testing a new russet potato breeding line that naturally resists the pests.
Commercial varieties bred from line PA99N82-4 would be the first with resistance not only to CRN, but also to northern and southern root-knot nematodes, says geneticist Chuck Brown. He’s in ARS’s Vegetable and Forage Crops Research Unit at Prosser, Washington. “PA99N82-4 also resists the viral disease corky ringspot, which is transmitted by nematodes and causes unsightly blemishes in tubers,” he adds. “Corky ringspot is also controlled by soil fumigation.”
CRN is problematic in the Pacific Northwest, where two-thirds of America’s potatoes are grown, and in Florida. Though fumigating the soil before planting suppresses CRN numbers, the practice isn’t cheap, with some chemicals costing $300 per acre. It can also harm nontarget organisms, including beneficial soil-dwelling insects.
