Brittle Snap Damage in Corn

by | May 17, 2019 | Corn, Field Crops, Weather

Washington County corn with brittle snap damage after a recent storm.
Photo Credit: Mark Mauldin

Recently, I received a call about a strange phenomenon in a Washington County corn field.   Some type of pest was cutting off corn stalks, so my first thought were cutworms. But, when I found out the cut off stalks were V8 stage corn, that was almost head high, I got confused. After a trip to the field, and some quick research it was determined the farmer was not dealing with the world’s largest cutworms or any other pest, for that matter. This phenomenon is called “brittle snap” or “green snap”. Both of these terms refer to rapidly growing, otherwise healthy corn that is snapped off at a node by high winds.

Brittle snap is just another item on the fairly long list of things farmers worry about, but can’t really do much about. Basically everything you would do to try to reduce the risk of brittle snap would also reduce corn yield potential. Positive things like good soil fertility, adequate moisture, and warm sunny days all increase the corn’s susceptibility to brittle snap. The more rapidly the corn is growing, the more susceptible the crop is.

Brittle snap is most often seen between V5 and tasseling, with the frequency increasing closer to tasseling.  This is the time frame associated with rapid growth. Yield loss associated with brittle snap is directly related to the number of stalks snapped. If 15% of the stalks in a field are snapped, it is reasonable to expect a 15% reduction in yield. If the damage occurs early enough (V5-6) however, the healthy plants have some ability to compensate for the lower plant population, so final yield losses could be somewhat less than otherwise expected.

Certainly this could be another factor to consider when it comes time for variety selection for next year’s crop.  Ask your seed dealer about varietal differences in the prevalence of brittle snap. There appears to be some variation between varieties, but due to the hit-or-miss nature of brittle snap damage, it should not be the primary basis for variety selection. For the crop in the ground, about all you can do is keep growing good corn, and hope the next round of high winds miss your fields.

Washington County corn with brittle snap damage. Rapidly growing corn snapped off at the node by high winds.
Photo Credit: Mark Mauldin

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For more information on brittle snap in corn check out the links below.
Storm induced breakage (greensnap) – Iowa State Extension 
Brittle Snap Injury in Corn – Pioneer 
Green Snap in Corn – Wyffels Hybrids

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Washington County corn with brittle snap damage after a recent storm.
Photo Credit: Mark Mauldin

Mark Mauldin
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