May 21, 2024

Drought relief brings unique happenings

2023: At the end

Rains finally fell on Illinois, particularly in August, when the soybeans need it the most.

BLOOMINGTON, Ill. — With the growing season shifting from June to July, the severe drought began to break apart in some areas of Illinois that then brought on other challenges.

Here are the observations of the second half of the growing season from Stephanie Porter, Illinois Soybean Association outreach agronomist and certified crop adviser, in a podcast with Kelsey Litchfield, ISA agronomic outreach coordinator.

Timely rains arrived in July to some locales, but not all regions of the state. What did you see?

Porter: There were some areas that got really heavy amounts of rain. They had gone from being so dry and plants were so stressed, then all of a sudden all of this rain came. So, it was another shock to the plants.

In some areas of soybeans I think they had 2 or 3 inches or more of rain all at once, and we saw perhaps a lack of oxygen for those soybeans. We started to see some yellow spots.

The other thing that happened this year that people were asking about: Was the corn was shorter overall due to the drought? A lot of farmers were commenting on that.

Shaun Casteel, Purdue University Extension soybean specialist, mentioned in an article of his how important it is for soybeans to have closed rows by July 1. That’s something we did not have.

In areas where they were able to plant in early April, we started to see our first fungicide helicopters for early planted corn in central Illinois the first of June.

The other phenomenon that happened that (University of Wisconsin Extension soybean specialist) Shawn Conley had commented on was that we had rain all of a sudden, so the soybeans started to grow again.

Some of them had gone back into an R1 growth stage after being R3. R3 is the important growth stage because that’s the one where we usually spray fungicides or insecticides and when we just start to get that smaller pod on the first four nodes on the top.

So, whenever that plant started to shoot out some more growth on the top, then that kind of took it out of the growth stage and took it back to R1. A lot of people were asking about that because then they held off on spraying fungicide or insecticide if needed.

Northern Illinois planted a lot later and they experienced the rapid growth stage in corn. It’s like the plant gets a burst of energy and the leaves are growing so fast that they kind of stick a little bit and when they come out they have raggedy edges.

When I was scouting our own farm I started to see a lot of waterhemp escapes not just in soybeans, but also in corn. The waterhemp was getting away from us because we didn’t have residuals working because of the drought.

What issues arrived after the rains by mid-July?

Porter: We visited a soybean field at Prairie City in mid-July that had some dead patches. The places that got the heaviest rains after the derecho were the first ones hit with this, but around mid-July I coined this as root-rot mania.

We had a lot of different things going on and one of those was phytophthora root rot. That was popping up all across the state and in nearby states. It was a little concerning because I was very familiar with the genetics of the variety in that specific field at Prairie City. It had great phytophthora resistance and would have a high rating in the seed guide.

The other thing that was happening was I had a couple of field visits in the north towards Waterman and another area where they were seeing a lot of yellow patches. The plants they sent for diagnosis had fusarium root rot. I had several others say they found three or four different pathogens, so how do they know what the main one was.

Normally, we don’t worry about fusarium root rot in soybeans, but we were seeing it this year. The curious thing is some of those fields were coming out of it later on. My theory is it was almost a shock to the system.

When I did the field visit to Waterman it was raining again and you could see those areas that had fusarium root rot were still saturated in the low-lying areas and they did come out of it. That field that we visited at Prairie City averaged 70 bushels per acre.

Were there reports of foliar diseases towards the end of July after the rains?

Porter: We saw a little bit of tar spot in central Illinois, but luckily it remained low overall. A lot of people had sprayed fungicide like we did on our own farm. We sprayed something that had good efficacy on tar spot.

We had never officially seen tar spot on our farm before. My cousin said he had seen it in Montgomery County. So, it was new for us.

They were seeing frog-eye leaf spot in the south. I think the key was it just started to get really hot. By July 27, we were starting to see some grain-fill in central Illinois in earlier planted corn.

Variable is the word that’s come up a lot from this growing season — when you talk about disease pressure, insects, it was just spotty. We talked about it when it came to harvest. Yields were variable, better than what some thought.

There were still plenty of areas dealing with the drought. Other areas got rain, but I think we tend to forget about the ones that were still suffering from dryness.

What were you seeing going into August?

Porter: We started to see some more rain around Aug. 7, those timely August rains that we needed for soybeans. That helped a lot.

There were some areas where Kris Ehler, an ISA soy envoy, reported seeing sudden death syndrome on Aug. 7 and soybean cyst nematode. So, it was kind of a hot topic this year. We are offering free testing through the University of Illinois Plant Clinic with ISA checkoff dollars helping to fund that.

The other thing that was not expected was they started to find white mold in the north. The were also some areas on our own farm, for example, where we started seeing Goss’s wilt on susceptible hybrids. Goss’s wilt is a bacteria, so it needs some kind of injury and we had hail during the growing season.

Bean leaf beetle feeding showed up by the end of August, especially in east-central Illinois. They were finding really high numbers and they were spraying fields late.

There were certain spots where they were reporting charcoal rot, which is not surprising because it shows up when it’s wet early and then dry. I think those were in isolated spots in western and southern Illinois.

Dry weather and heat was the theme in late August, early September, and earlier planted hybrids started to turn quickly by Sept. 5. What did you see then?

Porter: We were at almost black layer on our farm in central Illinois where we planted the first week of April. It was also around this time that (U of I entomologist) Nick Seiter and (Illinois Natural History Survey state survey coordinator) Kelly Estes were surveying Illinois soybean fields and found dectes stem borer that started to pop up the end of August, first of September, in western and southern Illinois.

Not that it wasn’t anywhere else, but that’s where I was receiving reports from. They’ll have more details about their pest survey at the Soybean Summit Feb. 1.

There was also a lot of people were splitting those stems late season and seeing that brown. The larvae may not be there from the stem borer and they were calling it brown stem rot. It’s just something to be aware of to make sure you know what disease or what pest is going on.

Overall, in areas like west-central Illinois, where David Wessel of ISA board was reporting, soybeans were turning quickly by mid-September with the drought. Matt Reardon, Nutrien Ag senior atmospheric scientist, was reporting on really alarming low river levels.

Shaun Casteel, Purdue University Extension soybean specialist, has been doing a lot of research on sulfur in soybeans and reported seeing great responses with sulfur in soybeans in the September timeframe.

The hottest topic the entire season overall was black moths. I was in the combine and black moths were everywhere. Everyone was asking me about them.

They were moths of green clover worms that you can sometimes find in soybeans. It’s not normally a major pest that we talk about, but by the end of September they were everywhere.

For all that happened in 2023, what should farmers have in mind moving forward into 2024?

Porter: Hands down, do not skimp on weed control. That seed bank has built now in the fields and it’s very alarming. I know some have put in fall herbicides.

There are other management practices we can do to help suppress weeds. Cover crops did do a good job at controlling weeds.

Farmers might have discovered that they have phytophthora or we had some stem canker in some areas and those types of diseases. They can look at their seed guide and see if the variety they chose for the coming year has good tolerance for disease like phytophthora or stem canker, and white mold for northern Illinois.

Tom Doran

Tom C. Doran

Field Editor