Think back to the spring of 2016. If you farm somewhere in the Midwest, it’s likely you remember a cold snap after a reasonably warm start to spring. If you had corn in the ground and it wasn’t up, emergence may have been affected. If it was up and temperatures dropped low enough to cause frost, you no doubt learned a few things about how corn responds to frost injury.

Kelly Herbick, technical product manager for DuPont Pioneer, worked with Pioneer sales professionals in areas where frost did occur on May 14-15 to collect information. Using a frost survey app, the team visited over 100 fields, making tissue damage ratings and taking stand counts.

Herbick studied the observations and summarized the findings. Her findings were published in Pioneer’s 2017 Agronomy Sciences Research Summary distributed to customers.

Here are 12 takeaway messages based on what Herbick and the Pioneer sales team saw in 2016.

1. Coarse soils are more prone to fluctuations in air temperature. Corn on coarse-textured soils was more likely to experience stressful emergence conditions from early planting.

2. Hybrid response varies. How corn hybrids responded to cold stress varied by genetics.

3. Cold soil temps at planting matters. Both cold soil temperature at planting and swings in temperature of more than 20 degrees impacted germination and emergence.

4. Several planting dates were impacted by stressed emergence. Some of the biggest impacts came with corn planted April 23 and April 27-29. Even though it didn’t frost in Indiana, several farmers observed that corn planted April 27 struggled to emerge.

5. Warmer temps after stress helps. A return to warmer temperatures aided crop recovery, Herbick notes.

6. Health of plant structures is a good indicator of survival. Frosted plants depend on seed reserves and an immature root system to regrow.

7. Other stress factors compound the problem. Plants slow to recover or plants that didn’t recover almost always faced another stress, Herbick says. These ranged from shallow seeding depth to starter-fertilizer injury.

8. Frost causes uneven crop development. Thinned stands and uneven crop development were noted as plants struggled to recover.

9. Account for leaf collars when staging plants after frost. Getting growth stages right is critical to following herbicide label directions, Herbick notes.

10. Avoid herbicide application immediately after stress. Observations indicated that herbicides applied within 48 hours after frost may have enhanced plant stress and slowed recovery of frost-damaged plants.

11. Expect higher moisture levels at harvest. Early-season frost damage may cause delayed crop maturity and variability in crop development, Herbick observes. The result can be higher grain moisture at harvest in the fall.

12. A slight yield reduction after severe frost damage is likely. Yield impact is difficult to predict after frost. Observations indicate that fields experiencing severe frost injury may see a slight yield reduction due to thinned stands and increased interplant variability.