In the past 7-10 days we have noticed corn plants leaning or flopping over.  With some examination, it appears that these plants have poor nodal root development (ie. Rootless Corn Syndrome).  The plants may otherwise look healthy as the seminal root system and the seed reserves continue to support plant growth.  However, without nodal root development, the plant cannot sustain an upright stance or normal growth.

Shallow Planting, Wet Soils or Poor Seed Trench Closure

Poor nodal root growth is often associated with factors that expose the crown of the corn plant to heat and drying.  Shallow planting (less than 1.25 inches) can force the crown to be positioned shallower than the normal ¾ of an inch and therefore run the risk of desiccation.  Planting or tillage in soils that are too wet and then followed by a stretch of dry weather such that the crown is exposed to sidewall compaction, excessively hard aggregates and air spaces has been a challenge for many growers in 2017.  Similarly, poor seed trench closure can run the risk of nodal roots being exposed to temperature and moisture fluctuations that are not conducive to growth.

Dry Surface Soils and High Temperatures

Surprisingly, the poor nodal root growth that we are seeing is not all a result of obvious planting problems or exposed growing points.  There is evidence of rootless corn in fields where the planting depth was at the 2 inch mark and in soils where sidewall compaction or open trenches were not factors.  In these cases, the surface soils were quite dry and in some cases, there was some surface cracking.  The other factor that needs to be considered is the relatively high temperatures that some of these fields have experienced.  It appears that high temperatures combined with bright sunshine, dry surface soils and perhaps some less than ideal soil coverage may have proven lethal to developing nodal roots.

Moving Forward

Rainfall is required to get new sets of nodal roots established on some of these faltering corn plants.  In some cases, inter-row cultivation that could move some soil around the base of the plant may be helpful.  If you have questions about this or other agronomy questions, please do not hesitate to contact your local Maizex Representative.

Greg Stewart
Maizex Seeds Agronomy Lead

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