Much corn in our area is beginning to mature, and over the next few weeks the rest of the corn plants will begin to die in corn fields all through our area, especially those that have been under severe stress.

Premature death of plants can indicate significant problems with stalk quality and lodging, especially those that died off in late August/early September, according to Clarke McGrath, Iowa State University Extension Crop Specialist for Harrison County.

Corn stalk and subsequent lodging problems usually result from stressed conditions, and this year July, August and early September were very stressful to much of the area. The dry weather caused plants to develop marginal root systems, which led to limited late season nutrient uptake. As plants "cannibalize" the stalk for these nutrients, stalk rots can set in and the plant is more prone to lodging.

The early season high moisture and cool temperatures may also contribute to our stalk lodging issues, as that made it very easy for the stressed plants to pick up a crown rot in April/May that accelerated stalk quality problems this fall with the dry conditions.

In field visits lately, McGrath has seen many corn fields are beginning to display stalk rot symptoms. Unfortunately, it will likely only get worse, as the majority of stalk rot problems will appear in later September and October.

In order to prevent lodging losses, try to scout fields for stalk rot during the next week or so. Fields that have problems can be identified and should be targeted for the earliest possible harvest.

While scouting for stalk rot, look for visible symptoms and test stalk firmness by pinching the lower internodes with thumb and forefinger. Healthy stalks are firm and can't be compressed. If a stalk can be compressed or feels soft, it is rotted and is a good candidate for lodging.

Check at least 100 plants per field, in different locations  Different hybrids and fields with different tillage, rotation, or fertilization histories should be scouted separately. If a field has more than 10-15 percent of the stalks rotted, significant lodging is likely.