Disease and Insects are Attacking Your Wheat Crop. Here's How to Know Whether to Make One Treatment or Two

As May winds down, Ken Ferrie is taking a look at some important agronomic decisions farmers can make now to improve the performance of their corn, soybean and wheat crops. 

Here are four topics he addressed in this week’s Boots In The Field podcast:

1. Timing Wheat Fungicide And Insecticide Applications
Flowering in wheat is underway in Illinois and other Midwest states, and farmers are looking at making fungicide applications. In the process many are evaluating whether to add insecticide to their fungicide application to get out ahead of the true armyworm (TAW) population which is significant this spring, says Ferrie, Farm Journal Field Agronomist. 

“I personally think it’s a good idea to suppress the armyworm and other pests, though the timing is not great,” Ferrie says. “By the time we see armyworms, most of these insecticides are going to be running out. But the application will help with those first-laid armyworm eggs and may help keep their overall number more manageable if a big problem develops like the trap counts indicate is likely.”

Ferrie says you may still have to come back with a second, more timely insecticide treatment if true armyworm pressure builds to high numbers, because the insecticides available offer only a week of residual control, approximately. 

Also, if you are dealing with head scab issues, Ferrie says don’t delay addressing it, thinking you might be able to treat it and knock out true armyworm and other insects at the same time. Trying to address head scab and pests in one application could be the proverbial situation of losing a dime to save a nickel. In other words, financially, you’ll probably be better off making two applications – one for the disease and one for insects.

This has been a tough year for the wheat crop, so far. Find out more here: Wheat Tour Finds Drought, Freeze Robbed More Wheat Than Expected, Surprisingly High Abandonment Now Pegged Across Kansas

2. Black Cutworm Are Feeding And Farmers Are Treating
Ferrie says he is seeing cut plants and shot-hole leaf feeding evidence in some corn crops, indicating black cutworm is at work. Some fields have seen enough impact from black cutworm that farmers have already moved in and treated them.

Traited corn provides some level of protection against the pest, but traited hybrids still need to be scouted, if feeding is observed. Fields planted to Double Pro hybrids that show damage need to be scouted from now until the corn crop reaches V4 to V5.

“If you apply an insecticide (with the planter) that handles cutworms you should be all right but don't take that for granted. Scout those fields,” he encourages. “These recent rains will help with our planter-applied insecticides, because the cutworm will crawl across the surface and will travel through the insecticide and be controlled.”

In fields with dry soil conditions, Ferrie says black cutworm often travels under the ground surface. In that scenario, an insecticide from a planter-applied treatment might not be as effective at controlling the pest. 

Damage can be particularly severe in weedy, late-planted corn after a soybean crop and in corn planted in flood plains. Wet springs that delay tillage or herbicide burn-down applications are often associated with black cutworm outbreaks. 

“But this week we saw shot-hole feeding and cut plants in tilled fields that had winter annuals in them when the flights took place,” Ferrie notes. “Cutworm are easy to kill, so don't drop the ball on this pest. Some of your non-GMO premium -- or the cost savings from buying a Double Pro hybrid -- should go towards managing cutworm if it shows up.”

Ferrie says some farmers have asked him whether they can control cutworm at the same time they make their post-applied herbicide application, and he says it can work but only if the timing for both is effective.

“Spray weeds with your post herbicide based on weed size, and address cutworm based on the amount of feeding you find. Don't miss the best window of treatment for either problem,” he advises. 

Need to know more about the impact of black cutworm? Check out what Ken Ferrie says in the article, Black Cutworm is Moving into the Midwest, Be on the Lookout

3. Ugly Corn Phase Is Underway
Some of the early, April-planted corn, now in the V3 to V5 growth stages, is entering what the industry commonly refers to as the ugly corn phase. Not every corn crop goes through this phase, but it isn’t uncommon and usually means the crop hasn’t been able to access or take up key nutrients – nitrogen, potassium and sulfur – to the degree needed. 

Ferrie says several different factors can contribute to the issue:
•    At these growth stages, a transition is underway in the root system, with seedling roots doing a hand off to the nodal roots which start to supply the crop nutritionally. This transition can create some stress and make the crop look a bit ragged and uneven.
•    Cool, wet soils can contribute to the condition.
•    Sometimes, in areas of excess rainfall, the nitrogen is pushed deeper into the soil profile and is less accessible resulting in crop stress.
•    Herbicide carryover from the 2022 season could also contribute to stress and the ugly corn phase.

Want more information? Check out this great article on How to Rescue a Troubled Stand

4. Use Ear Counts For Yield Projections
Ferrie says now is a good time to be stretching measuring tapes, getting stand counts, evaluating uniformity and predicting ear counts. If there are gaps in the crop where plants are missing, dig into the gaps to evaluate what happened.

“Right now, we can still identify the cause, or at least break it down to a few contributing factors,” he says. “Later on in the summer, the evidence will be gone, and all we will be able to say is that we have a gap – and maybe take the easy answer and blame it on seed quality.

Let's get our stand counts and projected ear counts done now when we have some evidence to tell us whether the missing plants are due to insects, seed quality or growing conditions. That will allow us to come up with suggestions on how to fix the problem for next year.”

Ferrie says high ear counts, not high stand counts, are what contributes to high yield outcomes at harvest. It’s an important difference to understand and evaluate. Learn more here: How to Reach Your Ear Count Goal

To get all of Ferrie’s agronomic insights and recommendations from this week, listen to the podcast here: