Floodwaters, delayed plantings, tornado damage and more have left Kansas in June 2019 almost unrecognizable from June 2018, and the changes have made this year’s growing season a whole new ball game. During the annual Spring Crops Field Day at the Southeast Research and Extension Center in Parsons, Kansas State University Extension professionals shared research and scouting results to help farmers strategize.
“The big question this year is what to do because there are so many options going on especially with how much rain we have had this spring and how realistic it is to get corn in,” said Gretchen Sassenrath, crop production agronomist. “The biggest thing when you look at crop production is the ability to maintain the yield capacity at each stage and that’s what producers need to examine when considering planting late corn.”
Pollination, seed fill and harvest efficiency will all be critical stages for the 2019 corn crop, Sassenrath said. Weather during those key periods could make or break yields for producers.
“Corn is a very determinate crop — meaning that it blooms once,” Sassenrath said. “Corn flowers once and if you have bad weather conditions during that flowering, you’re done — that’s the challenge of growing corn.”
The question for late-planting producers in 2019 is whether or not it’s possible to avoid summer heat and capture fall rains in order to produce a quality corn crop, Sassenrath said.
“Planting now would move tasseling from June to middle of July and in a normal year that would put tasseling happening in the driest part of the year,” Sassenrath said. “Then we would move the dough stage moved to the middle-end of August and have hot temperatures when we’re trying to finish up.”
While 2019 has been cooler than average in heat unit accumulation, Sassenrath said there are no guarantees the lower temperatures will continue or that the crop will get enough moisture late in the season to maintain yield.
“If you can schedule moisture around pollination — go ahead and plant your corn,” Sassenrath said. “The biggest problem the study found was a big drop in test weight with a late planting and the grain moisture was a lot higher.”
“I have become more and more concerned in recent years with southern rust in corn because it is getting warmer sooner in the spring,” said Doug Jardine, plant pathologist. “As it gets warmer earlier in the spring, some of these diseases that blow up from the south also get established earlier.”
While the warm, wet conditions of 2017 made the year memorable for the disease, dry conditions eliminated most of the southern rust cases in 2018, Jardine said.
“There was very little rust in 2018, and it didn’t get here particularly early,” Jardine said. “June and July were dry last year and so under those extremely dry conditions, southern rust didn’t really have a chance to get started.”
As temperatures in southeast Kansas warm up sooner year after year, southern rust becomes an issue to watch earlier and earlier.
“Twenty years ago when I talked about southern rust in Kansas, we would say it typically shows up about the first of August,” Jardine said. “Now I would say that in recent years southern rust is typically showing up in early to mid July.”
A typical pattern is for southern rust to form down in the Mississippi Delta, creep into southeast Arkansas, move up to northwest Arkansas, and then make the jump to southeast Kansas, Jardine said.
“By the time we can physically see southern rust on the plant, it has probably already gone through two or three life cycles,” Jardine said. “If I find rust on July 1 down here, it’s probably been in the field since at least June 15 — that time period is how long it takes to build up to detectable levels.”
Southern rust has been shown to cause significant yield losses in corn if left untreated. Jardine suggested scouting fields for large areas of blighting on leaves and a fine cloud of yellow-orange dust from the rust pustules.
“You get circular, almost graham cracker-colored pustules with yellow halos,” Jardine said. “One of the unique characteristics of southern rust is it is very rare to see those pustules on the bottom side of the leaf.”
While it is too late to treat for Fusarium head blight for 2019, Jardine suggested scouting for the disease in wheat in order to assess damages and make efforts to clean the effected wheat before delivering it to elevators.
“If you go out in the wheat, fields now, head blight is fairly easy to find,” Jardine said. “So if you have decent looking wheat, hopefully you put down a fungicide at bloom time to limit head blight losses.”
On his way to the Spring Crops Field Day, Jardine said he scouted several fields between Manhattan and Parsons and found numerous cases of head blight — as predicted by data earlier in the year.
“We know the critical time for infection in Fusarium head blight is when the wheat is blooming,” Jardine said. “We were into that critical period around May 5 and at that time our prediction tools showed all of southeast Kansas as high risk.”
Adverse weather conditions were once again to blame for the prevalence of the disease across the state.
“I won’t say it’s the worst year we’ve ever had for head blight but it was a pretty severe year across a large part of the state because of all of the spring rains,” Jardine said. “Even up in northwest Kansas, they were a little bit worried about Fusarium head blight.”