A mid-November freeze damaged vineyards in Walla Walla, high-elevation winter wheat around Waterville, Wash., and fruit trees in The Dalles and Hood River, Ore.
The extent of the damage in those and other parts on the eastern sides of both states will be more fully known in the spring, when damage is more evident. But growers have made early assessments.
It appears cherry and pear trees may be the hardest hit in The Dalles and Hood River, according to Jay Pscheidt and Lynn Long, Oregon State University Extension specialists.
Trees damaged by cold are more vulnerable to disease and pests.
Pscheidt and Long advised growers copper-based pesticides could be used to prevent bacterial canker if an orchard and those around it do not have a history of copper use or resistance.
Removing damaged and diseased wood by winter pruning may help trees recover and slow or stop the spread of disease, they wrote in an advisory to growers. Summer pruning in diseased blocks should be considered, they said.
Temperatures dropped to single digits in many parts of the region, Nov. 10-17. The impact was accentuated by it being a sudden drop from much higher temperatures, plants did not have time to build much winter hardiness, said Tim Smith, Washington State University Extension tree fruit specialist emeritus in Wenatchee.
“It’s worrisome. I wouldn’t be surprised to see some damage,” Smith said.
Everyone looks for bud damage and that’s what occurs in spring frosts, he said. But fall and winter freezes damage tree trunks and lower limbs, he said. Trees flower in the spring and then collapse from trunk damage, he said.
Younger trees have more vigor and are slower to go dormant so they are more susceptible, and cherries and peaches are among the most vulnerable, Smith said.
“We had a little more cooling and winter hardiness leading into it in the north, but fieldmen are concerned about some cherry damage,” said Dan McCarthy, Okanogan County Pest Control agent.
Andy Gale, manager of Stemilt AgServices in Wenatchee, said Sweetheart cherry buds show some browning. “My hunch is it did a little damage, some thinning and that will be a good thing overall for the market,” he said.
So far sampling hasn’t shown any damage to rootstock and one-year trees at Willow Drive Nursery, said Neal Manly, sales manager at the nursery south of Ephrata. He said he doubts there’s any damage at neighboring fruit tree nurseries in the northern Columbia Basin. Temperatures were lower farther south, he said.
Winegrape vines were damaged in Walla Walla but sampling shows the rest of the region in good shape, said Kevin Corliss, vice president of viticulture, Chateau Ste. Michelle Wine Estates in Woodinville.
“The hardiness level was 6 to 10 degrees lower than the temperature, so vines were fairly hardy when the freeze came,” Corliss said.
While some growers in Walla Walla will be hard-hit there shouldn’t be much of an overall crop reduction, he said.
Some club and newer varieties of soft white winter wheat are showing poor color in certain places on the Waterville Plateau, said Kevin Whitehall, manager of Central Washington Grain Growers Inc. in Waterville.
It’s the highest wheat region in the state at about 2,500 to 2,800 feet. That makes it colder. The freeze, winds and lack of snow cover for insulation did the damage that doesn’t appear widespread so far, Whitehall said.