June 15, 2007

The June 8 freeze in the Nebraska Panhandle has caused some significant crop damage in scattered areas. It appears that much of the winter wheat crop has survived with little to no injury, especially in the southeast Panhandle (Deuel, Garden, and Cheyenne Counties) where wheat was furthest along in development and temperatures did not generally go below freezing at all or for very long.

IANR Photos by Gary Hergert)

Figure 2. Corn plants damaged by June 8 freeze. Damage ranged from only top growth being killed to plant tissue death down to the growing point.At the higher elevations and latitudes, near the Wyoming or South Dakota borders, temperatures were lower — as low as 22°F. Wheat in these areas was generally not as well developed and was more susceptible to serious freeze injury. It appears that some of this later wheat is going to have significantly reduced seed set resulting in totally or partially blank heads. Some irrigated growers have started to hay these fields and hope to be able to come back and plant dry beans. Most dryland wheat growers will probably wait until harvest and see how badly they were hurt. Damage seems to vary considerably from field to field and even within fields. Dry conditions in much of the Panhandle limit replant options for dryland growers.

Dry beans that were emerged have been seriously injured or killed in some fields and many fields will be replanted. Corn was also damaged, but much of it is recovering because the growing points were not killed (see Figure 1). Recovery depends on the degree of freeze injury which varied depending on temperature, duration of the low temperatures, soil water status, stage of crop development and even hybrid.

Jerry Darnell, manager for Western Sugar Co. in Scottsbluff, said company representatives have visited all their sugar beet fields and didn't find any freeze damage. Sugarbeets are quite cold tolerant due to the high sugar levels in the leaves.

We have looked at corn samples from several locations north and west of Scottsbluff. Damage ranged from only top growth being killed to plant tissue death to the growing point. Plants that were 4 to 5 inches tall and had 3 to 4 inches of undamaged live tissue above the growing point should recover if they have adequate moisture. Plants that had more than 50% of the plant tissue dead above the growing point will have difficulty recovering and will have lost most of their future leaves. An interesting observation has been that fields or portions of fields that were stressed from dry conditions, recent postemergence herbicide treatments, or cultivation seemed to have suffered more frost injury than fields where corn plants were not stressed.

Drew Lyon
Extension Dryland Crops Specialist
Gary Hergert
Extension Soils Specialist
Both at the Panhandle REC, Scottsbluff