Green snap is the condition where rapidly growing stalks are broken by strong, sudden winds associated with thunderstorm downbursts. Over one-quarter million corn acres suffered significant green snap from the June 29 storm, based on estimates from field crop specialists. Fast-growing corn is very susceptible to green snap damage. These are two periods of very rapid growth in the corn plant. New cell walls are extremely fragile and need time to harden and develop.
Several factors affect green snap.
The timing and the velocity of the wind are the most important, coupled with the hybrid involved. Because it is only an occasional problem, hybrids are not evaluated for resistance to green snap. Heavy wind during cool morning hours will cause more green snap than if the wind occurred during the heat of the day. Corn that experiences green snap at or near the soil surface will probably not produce a ear. When the damage occurs above the ear, two sources, the University of Minnesota and the University of Nebraska-Lincoln, differ in how much damage to expect.