Finding diseases and insects in your cornfields is nothing new for most farmers. From armyworms to rootworms, leaf spot to stalk rot, something is bound to rear its ugly head during the growing season. But there are some diseases and pests that are becoming more common.

“A not-so-new disease that’s becoming more common is Diplodia leaf streak,” says Paul Vincelli, University of Kentucky plant pathologist. “This fungal leaf spot disease looks like Northern leaf blight, so it may be easily overlooked. I haven’t seen any serious cases, however, with increasing occurrence of this disease. But there may be certain highly susceptible hybrids that could unexpectedly get hit hard sometime in the near future.”

One disease that seems to make its way to the forefront of lists (and fields) is Goss’ wilt/blight.

“Goss' bacterial wilt and blight was and continues to be important to us in Nebraska, and especially after a severe weather event that wounds corn, such as hail, high winds and sandblasting,” says Tamra Jackson, plant pathologist at the University of Nebraska-Lincoln. “Producers with fields that have a history of the disease (or neighboring fields) should be careful to select more Goss' wilt-resistant hybrids in those locations since the bacteria overwinter very well in infected crop residue from the previous year(s).”

Of course, the other common denominator in most expert outlooks is the weather.

“If it is dry we’ll see very little disease,” says Alison Robertson, Iowa State University plant pathologist.

And while the dry weather might hinder diseases, the wet weather may be playing a role in lower insect populations.

“Weather can always play a role limiting or encouraging outbreaks. The low populations of rootworms we’re seeing might be related to wet springs we’ve had recently,” says Ron Hammond, Ohio State University entomologist. “However, our inability to predict what the weather will be over a long time period that can greatly affect insect populations limits our capacity to know what might happen with insect populations.”

 

Some new information when it comes to pests falls into the refuge requirements for 2011.

“There have been several changes in refuge requirements in 2011,” says Erin Hodgson, field crop entomologist at Iowa State University. “Growers should be aware of the various planting options provided by seed companies so that they are still compliant. I encourage farmers to scout for insects on a regular basis throughout the summer, including digging up roots and assessing rootworm feeding injury. Knowing this year's pest pressure will help make informative seed selections for next year.”

 

Ohio: Western Corn Rootworm, Western Bean Cutworm, Gray Leaf Spot, Northern Corn Leaf Blight, Eyespot, Common Rust, Stalk Rot

Illinois: Southern Rust, Diplodia Leaf Streak

Missouri: Black Cutworm, Japanese Beetle, Fall Armyworm, Corn Earworm, Diplodia Ear Rot, Stalk Rot, Gray Leaf Spot, Southern Rust, Common Rust

Nebraska: Corn Rootworm, Western Bean Cutworm, Grasshoppers, Goss’s Wilt/Blight, Gray Leaf Spot, Stalk Rot, Southern Rust

Minnesota: Eyespot, Stalk Rot, Goss’s Wilt/Blight, Northern Corn Leaf Blight

Kentucky: Corn Borers, Western Corn Rootworm, Fall Armyworm, Corn Earworm, Brown Stink Bug, Goss’s Wilt, Diplodia Leaf Streak, Southern Rust

Iowa: Stalk Borer, Armyworm, Corn Leaf Aphid, Goss’s Wilt, Northern Corn Leaf Blight, Stalk Rot

Indiana: Western Bean Cutworm, Corn Earworm, Fall Armyworm, Western Corn Rootworm

Wisconsin: Goss’s Wilt, Anthracnose, Eyespot