LONDON MILLS, Ill. — As the corn planting season wraps up,
producers should turn to stand evaluations and insect and disease
Lance Tarochione, DeKalb and Asgrow territory agronomist,
said the best thing farmers can do during the emergence stage is check for
“It’s a great time to identify if you have any issues with
your planter as far as depth of seeding or seed-to-soil contact issues or not
getting the seed furrow closed properly,” he said.
“When corn is at V1-V2, it’s a great time to walk the field
and evaluate the performance of your planter. You can’t fix it at the point, but
you can at least identify issues and improve them before next year.”
Growers also should monitor for emergence challenges such as
crusted soils and seeds that are struggling to get out of the ground.
Tarochione said there have been issues with crusted soil in
corn that was planted in the April 26-27 window before the extended period of
rain and cool weather set in.
“In some of those fields where the corn was planted on those
days, in particular, those stands were very slow coming and struggled and
there’s been some fields that got rotary hoed and there have been some fields
with marginal stands and perhaps even a little bit of replanting,” he
“Watching that crop coming through and making sure there’s
not a crust and making sure you’re getting a good leave-able stand is pretty
critical. But if you do have to replant, obviously, the sooner you can determine
that, the sooner you can get it done and the less yield potential that has been
Insect and disease scouting remains a top priority even in
the corn’s early development stage.
Most of the insects that could impact corn early are the
seed-feeders such as wireworm, grubs and seed corn maggots that are active in
cool soils early in the season.
“Rootworm doesn’t come along until much later or our normal
above-ground pests like corn borer and things such as that are much later in the
season, so it’s more of the secondary pests that you may be seeing now,”
“Cutworm, perhaps, would be getting started in some areas,
so you need to be watchful for that. Basically, the seedling and seed-feeding
insects are going to also potentially interfere with emergence and negatively
impact stand establishment.
“If you have plants that are missing, plants that failed to
emerge, when you dig up those seedlings, look for signs if there was insect
damage, a disease issue, a seed issue, a planter issue, a soil issue or
something prevented that seed from emerging and diagnose what it was that
prevented that seed from coming up.”
Wet and cool soil temperatures — less than 50 to 55 degrees
— can delay seed germination and emergence and predispose corn seedlings to
disease. Seedlings become more susceptible to infection the longer a seed is in
the ground before emergence and the more stress germinating corn endures.
Seedling blight is one disease that could appear this time
of year, with pythium being the most common.
“Rhizoctonia, fusarium and some others are out there, but
pythium is probably the most common and typically most active in cold wet soil,”
“We’ve had the cold, but we really haven’t had the wet, so I
wouldn’t anticipate a lot of seedling blight this year, but in some isolated
areas where you had a wet soil or caught a rain and had the right conditions and
cool wet soils is what pythium likes.”
The agronomist also addressed speculation of the severe
winter’s impact on insects and diseases in crops.
From a disease standpoint, Tarochione said it’s all about
what happens from here forward.
“A warm wet winter would be better for breaking down crop
residue, which is what harbors a lot of our diseases. But I really think it
would be a stretch to say winter weather has any impact on diseases,” he
However, the winter may have some impact on insect
populations, but one shouldn’t let down their guard.
“Some of our insects overwinter here, if it was in fact
severe enough to reduce those populations. The problem with it is you’re never
going to know whether it did or didn’t,” Tarochione said.
“So you still have to be on-guard for those insects if you
are using an insecticide or seed treatment to protect yourself from those
insects. I don’t think anybody is going to be cognizant enough to say that the
winter wiped them out and tell you that you don’t need to worry about that
issue. People speculate on that a lot.
“It’s a very popular topic of conversation, but it is a
little bit of an academic argument because there’s no way to know what the
pressure of those insects are, so you still have to be prepared for them as
though they’re there.”
He said the biggest impact of the severe winter was it made
people apprehensive to start planting because it wasn’t warming up and there was
a lot of replanting the previous spring.