Thirsty crops struggle early on

BLOOMINGTON, Ill. — The drought that impacted much of Illinois was a primary concern in the first half of the 2023 growing season.

Stephanie Porter, Illinois Soybean Association outreach agronomist and certified crop adviser, and Kelsey Litchfield, ISA agronomic outreach coordinator, peeled away the layers of this past crop season in a recent podcast.

Here are Porter’s observations through the first half of the growing season.

What did you observe early in the season?

Porter: We had some that early-planted soybeans and a later frost, and by May 9 we were seeing some frost injury in central Illinois of those early April-, late March-planted soybeans.

A question that we had was, how will they do? At least in my neck of the woods, we did have a lot of issues perhaps with some water at the beginning of the season and then we had some crusting.

By the time we got towards the end of May, it hadn’t rained in a while. My first indication was when I was traveling the state and a field near Pekin already had irrigation running. That was my red flag that it’s getting a little bit dry at this point in time.

Did you see any unusual occurrences during the growing season?

Porter: Some other weirder things that happened this season, and I had seen it previously, was the silver leaf corn in central Illinois. Basically, we had really low humidity, then we had a cool spell at night, and it made the leaves turn a silvery color. The south was struggling with armyworms at the end of May in some wheat fields.

It was a cool season overall. One of the examples was (University of Illinois postdoc in crop physiology) Connor Sible had via the former Twitter about his research where he was seeing positive responses to phosphorus and potassium just because of the cooler season with corn.

It was dry in late May and into June and we started talking about drought. What happened next?

Porter: The next thing that happened is the crops were really growing — not just crops, but cover crops and they were taking a lot of the moisture out of the soil that had been there.

One good thing we recently heard at a field day was a reminder that the cover crop growth helped the roots get pretty deep in the ground, especially with corn. It helped them not only to have just good stability, but be able to reach moisture at greater depths. That did help the plant as well going forward.

We went a while without rain in a lot of different places. At one point, starting in June, that’s when we really started to worry about some of those residual herbicides working.

We had some Extension specialists saying to go ahead and spray those. Their hope was that it would still rain.

Overall, we did not see any major issues with cutworms. That’s one of the first pests we think about especially in corn, but also in soybeans. Southern Illinois did have some of those the first of June.

We worry about rootworms hatching and overall it was not too bad with rootworms this year in corn, but that northwest area of Illinois is definitely going to be a watch-out area and of course the further north we go we’re always watching out for rootworms.

There were areas in western Illinois where they hadn’t had rain since planting and up until June 4. It started to get a little bit hot, as well. The drought hit hard by mid-June, and there were conversations comparing it to 2012.

Anything else that you’re seeing during your field visits?

Porter: The concern for soybean cyst nematode was there. It can be worse in drought seasons. By June 14, which is about 45 days after planting, you can start seeing soybean cyst nematodes females. So, that was the time to start looking for them.

Rootworm injury started to show up about mid-June, especially in the Champaign area, where it was just so dry, and then adults started to emerge.

Soy envoy Kris Ehler (of Thomasboro) as well as (U of I weed science specialist) Aaron Hager started to report herbicide carryover in soybeans. The previous year in east-central Illinois was also very dry, and so without have precipitation they were seeing the effects of herbicides coming back and causing some symptomology overall.

The one kind of alarming thing that happened, and we hadn’t seen soybean aphids in a long time, but in northern Illinois towards the end of June soybean aphids started to show up. It overwinters in buckthorn and this year scouting would have paid off and they did spray some of those soybean fields for aphids if they were over threshold.

By June 22, most of the state was completely dry. One of our soy envoys, Kelly Robertson (of Benton) had sent a photo where corn in southern Illinois was hanging on because of dew that was trickling down near the roots because of the great engineering of the corn leaves. They were just hanging on by a thread.

Also in southern Illinois as wet got to the end of June, Leo Rocha, (a post-doctoral researcher at Southern Illinois University in Carbondale), a ISA soy envoy, reported the first root-knot nematode, which is a problem in several counties in southern Illinois.

What was your message to farmers by late June with the conditions they were dealing with?

Porter: As we approached the end of June, farmers were starting to go into freak-out mode. We were approaching critical time, especially with corn for pollination, and we knew that we needed to get some rain at that time.

The other thing that was on farmers’ minds was should they even spray a fungicide/insecticide, usually fungicide for corn, because it was so dry. We weren’t seeing any signs of diseases when we scouted.

The third thing would be concern about herbicides not working. There was no rain to help with the activity of the residuals. I saw some pictures of weeds in fields at this time. There were reports of potassium deficiency by late June.

There were also reports of spider mites, and Nick Seiter, University of Illinois entomologist, recommended not to mow ditches as a result. What was that message?

Porter: The hot topics at the field days were the potassium deficiency that everyone was seeing. The message was it wasn’t necessarily that the potassium wasn’t in the soil — it was just because we didn’t have the moisture in the soil for the potassium to be up-taken by the plant.

Spider mites were on everyone’s mind. There were some outbreaks at various times throughout the season in western Illinois, as well as some places in southern Illinois. So, people were scouting for spider mites.

Another message with spider mites is we were trying to let people know that they need to make sure they were using an insecticide that controls spider mites.

Overall, farmers were reporting a lot of stressed crops and it was starting to get on the edge to where were really worried toward the end of June. Double-crop soybeans were also being planted toward the end of June in southern Illinois.

The drought monitored began to mirror 2012. However, yields were much better than expected. How?

Porter: I would attribute that to breeders, product managers and those who are out there year in and year out evaluating new hybrids and new soybean varieties and are doing their job. I think we saw that.

In my past, I know they specifically would try to stress corn hybrids, for example, on purpose or put their in locations with more stress just to see how they perform. We want to make sure we want to get high yield, but we also want to be able to overcome the stress. I definitely think we’re there.

We still have a lot of farmers using what I would term as older hybrids, as well. So, I just think that they’re good hybrids. We don’t necessarily use the newest hybrids every year.

Many companies still have some that have been hanging around for a while and there’s a reason for that because they can overall perform.