Cold weather stress on corn and soybeans
Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.It appears that most of Michigan’s emerging corn and soybean crop has made it through the recent cold snap in fairly good shape. Regional reports from MSU Extension educators located in the primary corn and soybean growing areas indicated overnight temperatures in the low 30s, and upper 20s the past week. Most of the state did not quite reach the critical 28°F threshold and avoided significant frost injury. However, some northern areas and isolated areas throughout the state will likely experience frost injury, and in extreme cases, mortality to soybean seedlings.
Check low-lying areas of fields where natural “air drainage” is restricted for frost damage first. To assess seedling viability, split a plant lengthwise through the stem. The growing point should be relatively firm and white or cream colored. Darkening or softening of the growing point indicates a nonviable (dead) plant.
Replanting of frosted areas in soybean may be warranted if these areas are extensive, however, as indicated above, it appears that most of Michigan escaped critical frost damage conditions. Seedlings that have not emerged were protected by the soil and should not have been affected by this week’s cold temperatures. Keep in mind that the growing point in corn seedlings stays below the soil surface until plants are at about the six-leaf stage. Therefore, corn seedlings can recover from frost injury even though much of the above ground part of the plant may die off. The relatively warmer temperatures forecast for the next few days should go a long way towards improving the condition and appearance of emerged corn and soybean in Michigan.