Although much of the western Corn Belt has experienced drought over the past couple of years, extreme weather events — including hail and high winds — have contributed greatly to local outbreaks of bacterial diseases in corn.
Adam Haag, Golden Harvest agronomy manager for the West region, is based in Nebraska and knows all about these weather events.
‘The weather extremes over the last couple of years in Kansas and Nebraska, like hailstorms that we’ve experienced, have created disease issues for us from a management perspective,” Haag told viewers at a recent Agronomy in Action webinar series program sponsored by Golden Harvest. “Wind and dust storms last spring created an environment for us with an increased level of disease pressure, so with inoculant in the field, we need to be proactive and be ready to manage those issues that will be out there.”
There are general recommendations to avoid infection and the spread of common bacterial diseases. (See table.)
Here are four common bacterial diseases that strike western Corn Belt fields, along with symptoms and potential management strategies from Golden Harvest agronomists:
1. Goss’s wilt. A true Nebraska original, Goss’s wilt was discovered and identified in Dawson County in 1969. “Goss’s can infect corn plants at any growth state, from very early on to late development,” Haag says. “There are two symptoms, including foliar leaf blight and systemic wilt.”
It starts with leaf freckles, and the telltale water-soaked lesions. As it progresses, those lesions kind of ooze out, Haag says. Eventually, it turns to scorching bright orange in color and can be misidentified as heat scorch. “But if you hold the leaf up to light, you can see the shiny surface and water-soaked lesions,” he says.
“Another symptom is the systemic wilt phase,” Haag explains. “If the plants are infected early enough, the disease can go systemic and impact the vascular system of the corn plant, which can end in plant death.” Both symptoms come from the disease entering the plant through some kind of wound.
GOSS’S WILT: Goss’s wilt was first discovered and identified in Dawson County, Neb., in 1969. (Photo by Tamra Jackson-Zeims, Nebraska Extension)
Starting in Nebraska, the disease has increased in distribution to include Kansas, South Dakota, Colorado, Wyoming, Montana, Iowa, Ohio and Wisconsin over the past couple of years.
“It is moving north and west over the years,” Haag says, “with some years worse than others.” Since a wound is needed to infect, hail and windstorms allow bacterium to enter through these kinds of wounds. Although it is rare, it may actually survive on seeds as well, explaining the distribution into the Eastern states.
To manage Goss’s, producers should look to their seed companies for guidance on hybrids with native genetic tolerance, Haag says. In late season, it is easy to see how hybrids vary. Some hybrids will be completely healthy and others alongside those same plants will show stress, no doubt affecting yields.
“Crop rotation has proven to be one of the best management tools,” Haag says, “but we also need to manage weeds and other plants that could be hosts like shattercane, foxtail and barnyard grass.”
For continuous corn, manage residue. “If you have corn on corn or multiple years of no-till, properly managing residue through fall tillage will slow the spread of Goss’s and give you a better chance to manage it,” Haag adds.
2. Bacterial stalk rot. “We had a small outbreak of bacterial stalk rot in central Nebraska in 2021, within about a 58-mile radius,” says Blake Mumm, Golden Harvest seed agronomist in south-central Nebraska. “You have the bacterium in the soil; it’s everywhere, worldwide.”
There are many different bacteria that cause BSR, but it is most common in hot and humid weather and on irrigated fields using surface water sources such as ponds, lakes, canals and streams. The pathogen has many other host crops such as potatoes, carrots, onions, tomatoes and cabbage, and early on, it looks like Goss’s.
“There is discoloration of the leaf sheath and stalk node,” Mumm says. “You see lesions and some browning on the leaf sheaf. The fields that we watched in 2021, at first, we thought it was Goss’s, but something wasn’t right. The telltale difference between BSR and Goss’s is the foul odor coming from the plant as the tissue decays from stalk rot and becomes dark brown, mushy and slimy. It smells like fermenting corn, but it is foul. Once you smell it, you remember it.”
The other difference, he says, is that not every plant will be infected. There will be hot spots in the field, but it is very random.