The University of Arkansa Extension Service reports it is receiving reports of some corn plants exhibiting “Rootless Corn Syndrome.” This can be a real problem in corn and although the name seems odd, it a very accurate description. Corn needs to be planted approximately 2 inches deep to help ensure that the nodal root system forms properly.
Nodal roots are the “anchor roots” that help hold the plant down. If the area where nodal roots form is at the soil surface or above the soil surface, the needed nodal roots won’t develop. In Arkansa this year, shallow planting was not likely the factor that is leading to rootless corn.
In most situations, corn was planted approximately 2 inches deep, but heavy rains over the last few weeks have eroded the raised beds down enough that now our effective planting depth is shallow, too shallow for nodal roots to form properly. It is striking sometimes walking across a field to see that one row is fine, but the next row has a high percentage of plants showing rootless corn syndrome.
Differences in planter depth or softness or hardness of a bed can lead to a lot of variability in the number of plants with rootless corn syndrome. If the planter was planting on the edge of the bed, this makes the problem worse. Twin-row planting can sometimes cause more problems because both rows tend to end up on the edge of the bed.
Below is an example of V2 stage corn plant showing rootless corn syndrome (left side) and one that has normal nodal root development (right side). Photo by Kevin Lawson, April 15, 2016
What will happen to these plants?
In most instances, these rootless plants without a nodal root system will likely die. Often a strong wind will snap the plants off at the soil level since they have no anchor roots. Another term used for this syndrome is floppy corn syndrome as the plant flops in the wind and eventually breaks off. The nodal root system is important for water and nutrient update. If the rootless plants survive, they will be smaller and yield from the plant will be substantially impacted.
What can I do now?
If rootless corn syndrome is noticed in your field, row cultivation that moves soil up around the plants can be helpful. However, on raised beds this tends to be difficult to do. If a high percentage of plants are showing rootless corn syndrome and row cultivation is not effective to move soil around the plant, replanting may be warranted.
If you don’t see any visual symptoms of rootless corn syndrome, it is still a good idea to dig up some plants to see how deep your corn was effectively planted and how well the nodal root system is developing. A plant with a poor nodal root development is more prone to root lodging later in the season. In general, rootless corn symptoms will begin to be noticeable at the V2-V4 growth stage.