Strong Storm Damage to Corn – What to expect?

Strong storms through the state may have caused issues with corn fields in recent weeks. Questions may arise regarding what to expect after the storm comes through, especially with regards to whether the crop will recover or what the yield impact will be. In general, if the plant is still undergoing vegetative growth or is in early reproductive stages (earlier than R2), it is possible some upright growth may occur. Some lodged plants may recover and exhibit goosenecking/bent stalks, but other damaged plants may not recover and lead to yield losses. However, once plants have entered into the grain filling stages (R2 and later), flattened plants will likely remain flattened through the end of the season.

Yield losses from root lodging (where the stalk remains intact) are most severe (up to 45% yield loss) when it occurs during pollination time (Table 1). Root lodging is less of an issue when corn is at vegetative stages (lower percent yield reductions reported in the literature). However, if corn becomes root lodged during the grain fill stages may be non-harvestable resulting in greater losses if the damage is severe and no harvest accommodation can be made to pick ears from plants almost laying flat on a field.

Table 1. Percent grain yield reductions reported as a result of root lodging at different developmental stages. Table originally published in Severe Storm Damage and Short-Term Weather Stresses on Corn: A Review, Crop Science 64(3):1129-1166. https://doi.org/10.1002/csc2.21212.

Regardless of the lodging type, ears will become closer to the soil surface and canopies may become more restrictive to airflow leading to lower grain quality and greater ear diseases. If a fungicide application occurred this year around flowering, the issues with ear disease formation may be reduced. Susceptibility to root lodging increases with increasing seeding rate due to more plant competition present (Figure 1).

Figure 1. Root lodging incidence (A) and greensnap incidence (B) as influenced by seeding rate. Graphic by Alex Lindsey, PhD, The Ohio State University. Image from AC-1054.

Green snap (stalk breakage) typically occurs in later vegetative stages but is also possible during reproductive stages (breakage above the ear or below the ear, prior to harvest) and can result in major yield losses. Seeding rate changes had limited influence on green snap occurrence (Figure 1B), suggesting damage corresponds more to genetic susceptibility or crop stage (susceptibility) when storms occur. Reports of yield losses as a result of greensnap suggested a more detrimental impact at seeding rates between 24,000 and 36,000 seeds/acre (Figure 2).

Figure 2. Corn grain yield as influenced by greensnap incidence across Ohio sites and years at (A) 18,000 seeds/A (seeds per acre); (B) 24,000–26,000 seeds/A; (C) 30,000–36,000 seeds/A; and (D) 42,000 seeds/A. The solid line in each panel depicts the linear relationship of yield and greensnap for each seeding rate range (the equations are described in the figure panels). Graphics by Alex Lindsey, PhD, The Ohio State University. Image from AC-1054.

If flooding or waterlogging conditions occurred with storms, corn becomes less susceptible to flooding damage as it progresses through the reproductive stages. It is unlikely that much yield damage will be experienced due to standing water associated with recent storm events when corn was already at reproductive stages.

To read more about these and other issues associated with strong storms, consult our recent OSU Factsheets AC-1054 (https://ohioline.osu.edu/factsheet/ac-1054) and ANR-0151 (https://ohioline.osu.edu/factsheet/anr-0151). More information on this topic can also be found in the full review article published in Crop Science - https://acsess.onlinelibrary.wiley.com/doi/full/10.1002/csc2.21212