WEST LAFAYETTE, Ind. — Stalk health is poor in many
Midwestern cornfields, meaning growers might need to take a “triage” approach
when deciding which fields to harvest first, said Purdue Extension agronomist
Drought conditions during corn grainfill caused much of the
affected corn crop to “cannibalize” itself, or pull carbohydrate reserves from
the stalk to meet the needs of developing grain.
The remobilization not only weakened stalks, but it also
made them susceptible to stalk rots. Weak and rotten stalks are prone to
lodging, which can make picking up grain with a combine difficult and ultimately
lead to yield loss.
“There are a lot of fields vulnerable to storms, so growers
need to prioritize the health of their fields for harvest,” Nielsen said. “When
we start harvesting corn in earnest, we need to get the weakest fields out the
While stalk breakage is easily seen when scouting fields,
identifying stalks prone to lodging can be harder. The best way to identify
compromised stalks is to pinch the lower stalk internodes to see if they
collapse from the pressure.
In some instances, Nielsen said pushing stalks out of the
way when scouting is enough to make weak stalks fall over.
“Fields and hybrids at high risk of stalk breakage should be
harvested as early as possible to minimize the risk of significant mechanical
harvest losses,” he said. “Recognize that hybrids can vary greatly for
late-season stalk quality, even if grown in the same field, due to inherent
differences for late-season plant health or resistance against carbohydrate
remobilization when stressed during grainfill.”
Stalk rots can get bad enough in some fields to spread to
the ear shank, where the ear connects to the stalk, and on into the cob. Shank
and cob rots can cause plants to start dropping their ears either spontaneously
or when bumped by a combine head.
Part of prioritizing the least healthy fields for earliest
harvest also means growers might not want to wait until grain dries down to 18
percent — the desired moisture percentage for harvest.
“This is not the year to let corn dry down further in the
field,” Nielsen said. “Get it out of the fields. Don’t be greedy about waiting
to get this corn down from 22 percent to 18 percent. You’re rolling the dice on
some of these fields.
“If a storm comes along, we’re not talking about leaning
corn. We’re talking about corn flat on its face.”