Production Blog

DECATUR, Ill. (DTN) -- There's nothing quite like the word "greensnap" to quiet a room. I saw it happen last week during a presentation by agronomists during the annual AgriGold Specialty Crops Conference. Nearly every presentation included a warning that farmers should brace themselves for it this year.

Recent heat has led to rapid plant growth. Couple that with a thunderstorm packing high winds and the recipe for potential greensnap is written. Field geography, hybrid genetics and herbicide applications also influence the likelihood.

The breakage of corn stalks by violent winds is a chronic problem in some states and more hit-and-miss in other states, depending on the year. Mark Grundmayer, an LG Seeds agronomist based in Nebraska, sees some almost every summer.

"Unfortunately, greensnap occurs when you have good growing conditions -- adequate nitrogen, moisture, sunlight and heat," Grundmayer said in a company news release. By contrast, he said years when drought stress results in shorter plants typically results in fewer greensnap incidents.

"When a corn plant responds to favorable conditions and grows fast, it might not have a chance to get lignin developed between the nodal plates," he explained, likening lignin to the ligaments in your knee. If wind hits before that material has connected those nodes, greensnap can occur.

OTHER FACTORS TO CONSIDER

Agronomists will occasionally argue about definitions. Greensnap is most often defined as the stalk breaking off below the ear around V12-VT (tasseling). The problem is more common at that stage because there's more plant material to catch the wind. When young corn still in the vegetative stages (V5-V8) breaks, it is sometimes referred to as brittle snap.

According to Grundmayer, the risk factor for greensnap rises if a crop has recently received rain or is under pivot irrigation. Plant cells are more prone to snapping when swollen with water.

Phenoxy type herbicides (2,4-D, dicamba, and clopyralid) stimulate rapid growth and also dramatically increase the chances of greensnap occurring, especially if applied a few days before a wind event.

Row orientation is a consideration in areas with elevated greensnap risk. "Storms typically come from the northwest," Grundmayer said. "Avoiding whatever row direction plays into the wind side can help."

Heavy wind during cool morning hours tends to cause more greensnap than if the wind occurred during the heat of the day. Strong-rooted hybrids give less at the base and can have more greensnap than shallow-rooted plants that have a tendency for root lodging. Fields with lower planting population also tend to have less snapping because those plants don't have to stretch as much, and the stalks are thicker.

STUDY GENETICS AND RATINGS

Still, hybrid genetics go to the top of the list of factors influencing greensnap. "Farmers in at-risk areas should select hybrids with strong greensnap ratings, but they shouldn't plant the entire farm to it," Grundmayer advised. "Hybrid diversity is important."

Greensnap is tricky to measure. There are a lot of environmental factors at play and normalized data is limited, explained Mike Popelka, hybrid product breeding manager at AgReliant Genetics.

"Anytime there's a greensnap event, we're taking scores on all the hybrids in the test plots," Popelka said. "And we're always exploring new screening methods -- like using a helicopter to simulate high winds."

Each hybrid is different. "One might be prone to snapping at the V5 to V8 period, but then it's rock solid in the pre-tassel period. The opposite might be true for another hybrid," Popelka said. "We spend a lot of time making sure our scores are right."

Other companies also rate for greensnap, but may not do them in the same way. Farmers should take time to understand how each company values those ratings when doing comparisons.

OH, SNAP!

When greensnap downs crops, Grundmayer encourages farmers to assess fields and make sure they're not just looking at the worst spot. "You need to get a good handle on exactly how much broke within the field," he said, adding that damage often isn't as bad as feared. "Drones are fantastic for assessing damage."

Of course, the biggest impact of greensnap is lost yield. But snapped corn also opens the canopy to more sunlight, increasing weed pressure.

Harvestability can be a problem and rows may be tough to distinguish. "Get in early if you can," Grundmayer recommended. "Whatever you can do to get everything that's out there in the combine and into the bin helps the bottom line."

To read the complete release from LG Seeds go to: https://lgseeds.com/…

For a previous DTN story on greensnap and how short stature corn might factor into managing for the problem go to: https://www.dtnpf.com/…

For a DTN story on wind damage and whether corn will stand back up again go to: https://www.dtnpf.com/…

For an Iowa State University article on greensnap go to: https://crops.extension.iastate.edu/…

For a 2023 University of Nebraksa study assessing the loss from wind damage go to: https://cropwatch.unl.edu/…

Pamela Smith can be reached at pamela.smith@dtn.com

Follow her on social platform X @PamSmithDTN

(c) Copyright 2024 DTN, LLC. All rights reserved.