Damage assessment map created by USDA-NRCS, USDA-FSA, and Nebraska Extension staff in Dodge County on July 6th.
Listen to this morning’s extension corner with Nathan Mueller on wind-damaged corn:
This is Dr. Nathan Mueller, your local agronomist with Nebraska Extension for Dodge and Washington counties. On July 5, storms with damaging winds estimated at 60 to 80 mph and some hail caused crop damage across the area including in Dodge and Washington counties. In Dodge County alone, about 64,000 acres of corn were damaged through green snap, pinched stems, lodging, and hail. As you evaluate crop damage, keep in mind the different kinds of wind damage that occur in corn.
Green snap or brittle snap is when the stem breaks at a node and becomes detached from the lower portion of the plant. Corn is more susceptible to green snap in the two to three weeks prior to tasseling during the elongation growth stages starting from V12 to tasseling. After stem elongation at tasseling, secondary walls thicken and lignification occur strengthening the stalk, thus there is less risk of green snap after tasseling. Unfortunately, many acres planted in early May were V12 and April planted corn was just starting to tassel. When green snap occurs below the dominant ear (V10-V12 nodes), yield loss of almost one to one can occur, so 25% yield loss with 25% green snap (Figure 1). In a 1999 simulated green snap injury study in Iowa, yield losses of 15% were measured with 25% green snap, 32% yield loss from 50% green snap, and 53% yield loss from 75% green snap. Green snap above the dominant ears will be less, about 10% yield loss per 25% increase in green snap.
Pinched stems (Figure 2) even though attached, will cause yield reductions. I did see a fair amount of pinched stems in fields following this storm. Yield loss from pinched stems and root-lodged plants (Figure 3) are harder to determine. Root-lodged plants will try to reorient themselves. Younger plants or late-planted corn will likely straighten back up, but goose-necked stalks will likely occur on early-planted corn.
Contact your crop insurance agent to review your policies on wind damage and have an adjustor visit your field 5 to 7 days after the storm to better judge plant recovery. For more information on wind-damaged corn, call me at 727-2775 or visit our local website at croptechcafe.org. Know your crop, know your tech, know your bottom line. This is Dr. Nathan Mueller, your local agronomist for Nebraska Extension on KTIC radio.
Figure 1: Green snap below the primary ears.
Bowed and pinched stalks.
Figure 3. Lodging of corn plants.
