Agriculture Research Service scientists in Prosser, WA, may have found a less expensive way to control corky ringspot virus vectored by nematodes.
Rick Boydston and Pete Thomas of the ARS and Hassan Mojtahedi of Washington State University have found that by rotating potato crops with alfalfa and spearmint, soil contaminated by corky ringspot disease can be controlled.
Corky ringspot is a brown, bull’s-eye blemish on tubers. A virus passed into plants by stubby root nematodes causes it. In areas such as Washington’s Columbia Basin where 5,000 acres are contaminated, growers have either stopped growing potatoes or gone to fumigation in the soil to kill the nematodes.
The sustainable, pest-specific approach of rotating crops causes nematodes to miss acquiring the virus because it can’t survive in alfalfa and spearmint. Second, the nematodes naturally shed the virus from their bodies by molting.
Given enough time, scientists believe nematodes that feed only on these plants eventually would rid themselves of the virus and thus pose little or no danger of infecting a subsequent potato crop.
Another key is to eliminate weeds in alfalfa and spearmint crops where nematodes can acquire the virus.