This is the time of year when much of the Corn Belt enters one of the most susceptible periods for wind damage to occur. In particular, strong winds during periods of rapid growth can cause green snap in corn. While this type of stalk breakage can occur anywhere in the Corn Belt it is much more common in the fertile, wide open plains of the central and western states.
The time period that hybrids are susceptible varies widely, but in general there are two periods where corn is most susceptible to green snap:
- Shortly after growing point emergence, approximately V5 to V8 growth stage – breakage will be below the growing point. Damage at this stage is less frequent and is often associated with growth regulator herbicides. Walking fields at this stage if you kick a plant it will audibly snap at the ground level. Snapped plants at this stage will regrow two tillers, one on each side of the stalk that will not produce a normal ear, but often produces tassel ears especially when the plant population is significantly reduced.
- About 10 days, or later, up to silking, V12 to R2 depending on growing conditions – stalk breakage will occur at the nodal plates (joints) just at or below the newly developing ear.
Plants that are rapidly growing at these stages have out-paced the lignin bonds that form at the nodal plates and are susceptible to breakage from forces that bend the stalk severely. Plants that green snap at this stage, have virtually no yield potential for grain and become non-productive weeds in the field using up available nutrients and water.
Conditions which favor rapid plant growth and contribute to hybrid susceptibility include the following:
- Warm, moist growing conditions
- Plantings in fields without wind breaks or other natural structures that slow or block high winds
- High rates of available nitrogen
- Planting dates that are later than normal
- High planting populations (more competition between plants)
- Conventional tillage – soils warm faster
- Corn following soybeans
- Soils with good organic matter are generally darker and have better tilth, promoting rapid growth
- Field topography characteristics and row direction relative to the wind direction
- Application of growth regulator herbicides such a 2,4-D or dicamba, especially applied late or when conditions are warm and humid
- Hybrid genetic differences – hybrids with rapid early growth are more susceptible to breakage
The sad part about this is most of these factors are the same as those which contribute to high yield potential.
Management factors that tend to lessen susceptibility to green snap include:
- Early planting – cooler conditions usually mean slower growth
- Side-dress, or in crop, nitrogen applications – balances the nitrogen across the growing season
- No-till plantings usually grow slower, at least in the beginning of the season
- Judicious use of growth regulator hybrids especially on more susceptible hybrids
- Hybrid selection, some are less susceptible than others. Though no hybrid is completely without risk. Check the seed guide rating and ask the sales representative for advice.
Planting multiple hybrids and varying the planting dates is also a very good management tool for protecting against risk of green snap. A potentially very awkward situation can occur when a hybrid in a field with the planter split with multiple hybrids snaps; nothing can be done as this most often happens well past the date of a replant. This is just one of the risks of this type of field management. An insurance policy that includes wind damage for areas that are at high risk is likely a good investment.
This is stating the obvious but the degree of yield impact varies with the severity of breakage, fields with less than 10% damage will have very little impact on yield because the surrounding plants will compensate for the stand loss with larger ears, benefiting from both more sunlight and nutrients.
Note: The information in this issue is based upon field observations and third party information. Since variations in local conditions may affect the information and suggestions contained in this issue, LG Seeds disclaims legal responsibility therefore. Always read and follow label instructions.
LG Seeds and design are trademarks of SCA Limagrain.
Download a copy of this Technical Bulletin: Tech_339 - Green Snap of Corn