To assess wheat freeze damage:
1. Wait until high temperatures are at least 40°F for 5 to 7 days. According to the projected weather forecast, most of the state will have high temperatures greater than 40°F the next 7 days. Assess freeze damage next Tuesday or Wednesday. Any earlier than the middle of next week may provide an inaccurate estimate of damage.
Figure 1. Healthy wheat head at the Feekes 6, jointing
growth stage. 50x magnification. Photo: Brenda Kennedy.
2. Freeze damaged wheat will have yellow, chlorotic growing points, limp leaves and/or a silage odor.
Figure 2. Healthy wheat head at the Feekes 6, jointing
growth stage. 20x magnification. Photo: Brenda Kennedy.
It is likely that the main stems, which are at jointing, will be killed by last night’s and tonight’s low temperatures. The key is to determine the number of healthy tillers that remain. This will help determine the yield potential of the field and ultimately the decision to keep or destroy the wheat crop.
More information will follow once we understand the scope of the problem.