Published online: Mar 20, 2013 Insecticide
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BOISE, Idaho-It appears the tiny winged insects that can spread the crop disease zebra chip in potato fields will overwinter this season, despite the city experiencing one of its coldest Januaries on record.


Zebra chip, which creates bands in tuber flesh that darken when fried, first arrived in the Pacific Northwest in 2011. It's caused by the Liberibacter bacterium, which can be harbored by aphid-like potato psyllids that tend to migrate to the region from the south during summer.


Andy Jensen, regional research director for the Idaho, Washington and Oregon potato commissions, found overwintering psyllids in Boise last season, but speculated a mild winter may have aided in their survival.


According to the National Weather Service, Boise started this year with the 10th coldest January since the 1860s, when weather records were first kept. For the month, the average temperature was 19.6 degrees, 11.7 degrees below normal.


Nonetheless, Jensen, an entomologist, had little trouble finding living psyllids when he searched the Boise area in early February, and again this month.


"It's a little surprising to me how well they came through," Jensen said.


No overwintering psyllids have yet been found near Twin Falls or east. Jensen hopes to soon research psyllid biotypes to determine which ones overwinter and which ones cause crop problems.


SOURCE: John O'Connell, Capital Press