Skip to main contentSkip to main content
You are the owner of this article.
You have permission to edit this article.
top story

Prepare for disease after wet start

Crop emergence

Once the plant is in the ground, look for any emergence or stand count discrepancies. 

A slow, wet start to planting season in the Midwest could mean a higher rate of disease pressure in fields this season.

Alison Robertson, plant pathologist with Iowa State University Extension, said these conditions are optimal for fungi and disease.

Late planting could also make for some pressure on crops throughout the summer.

“We could have a busy spring,” Robertson said. “Most diseases are driven by moisture. They are delaying planting, which has some ramifications on the growing season, as it means we will get to tasseling later on in July, and most of our leaf diseases ramp up going into August. That means there’s more risk of disease going into grain fill.”

The immediate problem for many growers will be the potential of soil-borne diseases, Robertson said. Pythium, fusarium and sudden death syndrome are a few of the possible issues, and being active in scouting is the only way to stay on top of them.

Once the plant is in the ground, look for any emergence or stand count discrepancies and determine if it was caused by seedling disease, insects or problems with the planter. Robertson said the best protection, particularly for soybeans, is ensuring the right seed treatment is applied.

“Examine your seedlings for symptoms of seedling disease,” wrote plant pathologist Darcy Telenko for Purdue University Extension. “Look for rotted seed, root rot, mesocotyl rot in corn, and yellowed, wilted seedlings.”

Tar spot has quickly spread across the Midwest, and Telenko noted that that remains one of the top concerns going into 2022. Recent research has shown the fungus causing tar spot can overwinter in the upper Midwest, and while a rotation can help, it is not a full solution. Tillage may also help reduce the onset of the disease.

Telenko also suggested farmers take a good look at what fungicides they are using and how much impact it would have on tar spot.

Having additional chances for fungus and disease pressure this year may have some producers considering a second fungicide pass through the field. Robertson said it would take severe disease issues to make that worthwhile in many cases.

“A few years ago, we had a cool growing season and many susceptible hybrids out there,” she said. “We had severe northern corn leaf blight before tasseling, which is very unusual. We had some people applying fungicide before tasseling. They had to go back three, four weeks later and do a second fungicide.

“In other places with tar spot coming in early, that might be another spot where another application would be needed. Typically, 90% of the time, you can get away with one application.”

Jay Fisher, who works with Nutrien Ag Solutions in Blairstown, Iowa, said he’s hearing added concern from producers who are looking to get their crop in soon.

“Look out for below-ground insects and make sure you have the right seed treatment,” he said. “We’ve been spoiled for a few years with nice weather early, but now it’s fighting us a little bit. We aren’t worried yet, because we can get the crop in quick still.”

While conditions favor disease in 2022, Robertson said she is hoping for the best.

“We could all of a sudden turn warm and dry and then there will be no disease problems,” she said. “Everything will emerge quickly and outgrow any pathogens. If that continues through the season, we need moisture to get disease, so we might not see it then either. That would be best-case scenario for a farmer.”

Be the first to know

* I understand and agree that registration on or use of this site constitutes agreement to its user agreement and privacy policy.

Related to this story

Find the equipment you're looking for

Get up-to-the-minute news sent straight to your device.


Breaking News