Idaho grain crops rebound better than expected following harsh winter

IDAHO FALLS, Idaho — The 2026 growing season has brought devastating losses for many grain farmers across southern and eastern Idaho, but overall damage could have been much worse, according to a University of Idaho researcher.

The combination of drought stress, frost damage and elevated pest and disease pressure following an unusually warm, dry winter forced many regional farmers to mow down large acreages of fall wheat and barley rather than continue raising them. Other cereal fields, however, have recovered surprisingly well.

“In some cases, it’s been as bad as you can imagine, with farmers having to mow, while in other cases some of the worst outcomes have been avoided depending on when and where the crop was planted,” said U of I College of Agricultural and Life Sciences Professor Juliet Marshall, associate director of the Idaho Agricultural Experiment Station and an Extension cereals specialist. “Overall, the crops recovered quite a bit more than I ever expected.”

Early-planted fall grains suffered the greatest damage. Winter temperatures never stayed cold long enough for crops to enter full dormancy, allowing plants to continue growing slowly and draw down soil moisture from November through April. The lack of moisture and snow cover stressed crops, stunting plant shoots, known as tillers, and causing seedheads to develop several weeks early. Stressed fields that matured too soon were especially vulnerable when freezing temperatures arrived in April, causing widespread frost damage.

In southeast Idaho’s Rockland Valley, a dryland production area, frost damage stunted plant growth and triggered new tillers to emerge and produce secondary wheat heads. As of July 10, some primary heads were already overly dry, while grain in secondary heads still needed more time to mature, delaying harvest.

Frozen tillers were also more likely to die, creating a layer of dead leaves and stems on the soil surface that could harbor disease.

Losses have been especially acute in the Magic Valley, where much of the fall grain was planted early. Eastern Idaho’s short growing season likely helped many grain farmers avoid more serious losses. As a rule, east Idaho farmers must wait until late fall to harvest sugar beets or potatoes, allowing those crops more time to grow and forcing farmers to delay fall grain planting. Late-planted fall grain had less time to grow over the winter and was less susceptible to April frost damage because it hadn’t passed the boot growth stage — when the developing seedhead swells inside the sheath of the last leaf to emerge, called the flag leaf.

Aside from frost damage, the warm and dry winter allowed disease-carrying pests such as aphids and mites to survive the winter in large numbers. Barley yellow dwarf virus, which aphids spread, and wheat streak mosaic virus, which mites transmit, have both been rampant throughout southern and eastern Idaho and have reduced yields. Pest populations were also high during the spring planting season, leading to unusually high rates of the two viruses in spring grains.

Marshall remains optimistic about the spring grain outlook, however, compared with what she predicted in early spring.

“The spring crop looks really good,” Marshall said. “There was some frost damage but not nearly enough to cause yield loss.”

Media contact

Juliet Marshall
Associate director of Idaho Agricultural Experiment Station
Professor and Extension specialist in cereals
208-529-8376, Ext. 115
jmarshall@uidaho.edu