Last December's frigid temperatures may have damaged 80 percent to 90 percent of Utah Valley's peach crop, and experts warn that 1991 winter weather isn't over yet.

Utah State University Extension Services agent Tony Hatch said that negative-teen temperatures in late December destroyed 90 percent of the state's stone-fruit crops (including peaches and apricots). Though those crops have provided only 20 percent to 25 percent of the valley's total fruit yield in the past, the losses still amount to a substantial loss in Utah County's $10 million annual fruit farming economy, said Hatch, the extension service's fruit specialist."Stone fruits are the third largest fruit crop in the valley. "And remember, we still have more winter months to get through."

Orem's W.M. Ercanbrack Fruit Ranch Co. owns 275 acres throughout Utah County, including peach orchards in Genola. Co-owner Randall Ercanbrack said Hatch's assessment seems valid from his standpoint.

"It's still probably too early to give a precise estimate, but I'd put our peach losses at around 90 percent. We've gotten hit pretty severely, at least from the cuttings I've taken so far."

Ercanbrack said winter frosts prove frustrating for fruit farmers because, unlike spring frosts, farmers cannot use wind machines or portable heaters in their orchards.

"It's a hopeless feeling because all those precautions just aren't effective or cost-effective during the winter."

Peach buds are typically damaged by frosts during temperatures minus-10 and lower. Late-December temperatures in some orchards were substantially lower than that, destroying buds in the process, Hatch said.

Also, trees usually start barking over and hardening (conserving fluids and sap) as early as fall, Hatch said.