IDAHO FALLS, Idaho-Potato virus Y infections in Idaho seed have returned to extremely low levels after spiking during the 2011 crop year, according to recently released results of the state's annual winter grow-out.
Of 846 winter grow-out seed lots planted in Brawley, Calif., 38.65 percent contained some level of PVY, which is the lowest amount recorded since the testing program began. By contrast, PVY infection surfaced in more than half of the 2011 lots.
The new data also shows 14.07 percent of lots had at least 2 percent PVY and are ineligible to replant to produce more seed, called re-certification. That's down from 18.84 percent in 2011 but still above 2010's record low of 8.27 percent.
"To me, these are really good numbers," said University of Idaho Extension seed pathologist Phil Nolte. "There have been some very serious increases in PVY in the eastern and central U.S. this year. Their PVY rates are off the scale."
In Maine, for example, Nolte said the industry may have to ease re-certification requirements for PVY to have enough seed. Nolte said several potato states have discussed emulating the program Idaho started in 2007, requiring enzyme-linked immunosorbent assay testing of leaves collected from grow-out plots. ELISA tests confirm the presence of disease in samples based on color changes caused by antibodies. The lab testing, administered by Idaho Crop Improvement Program, is financed through grower certification fees.
Idaho previously relied solely on visual inspections, rendered unreliable by new PVY strains that are less symptomatic and potato varieties, such as Russet Norkotah, that display few visual symptoms.
SOURCE: John O'Connell, Capital Press
http://www.capitalpress.com/newsletter/JO-Growout-032213