Corn Leaf Reddening

This past week we have seen corn leaves in several fields that have turned red. In the past few years, we have been concerned about the symptoms of corn stunt which is transmitted by the corn leafhopper. In the fields I looked in, the leaf reddening was caused by two things: pasture mealybug or poor pollination. 

Some corn plants had yellowed or reddish leaves on the bottom of the plant. These plants were found only on the field edges up to 3-5 rows in, and bordered either the grassy roadside ditch or pastures. The grass in these pastures was infested with pasture mealybugs and the insects were moving into the corn fields. 

Pasture mealybug damage to corn leaf

So far, I have only found the damage to affect the plants on 4-5 rows into the field. I do not think this is economic damage; mostly because the leaf damage is below the ear leaf.

Leaf damage cause by poor pollination

In the other fields where I found leaf reddening, the red leaves were above the ear. Inspecting the ears of the affected plants, I found poor pollination to be the cause. When the ears on the plant are not pollenated well, or removed, the plant energy that was intended to go to the ear and fill kernels has no where to go and the result is leaf reddening.

There is not much to be done for either of these problems as one is not economic and the other is unmanageable. 

So far this year, I have not found corn leafhoppers in Calhoun, Refugio or Victoria Counties.  They have been found in Wharton, keep a look out for them in fields that are tasseling or have not yet tasseled.