LONDON MILLS, Ill. — As the corn planting season wraps up, producers should turn to stand evaluations and insect and disease scouting.

Lance Tarochione, DeKalb and Asgrow territory agronomist, said the best thing farmers can do during the emergence stage is check for uniformity.

“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 said.

“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 lost.”

Scouting Mission

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,” Tarochione said.

“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.

Early Indicators

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,” Tarochione said.

“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 said.

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.