Corn Pests to Scout for Now

July 19, 2009 07:00 PM

Sara Schafer, AgWeb Crops Online Editor
What's crawling around your corn fields? If you haven't ventured out between the cornstalks lately, several pests could be feeding on your precious corn without your knowing it.
Bob Wright, extension entomologist at the University of Nebraska-Lincoln, says a couple of insects of interest now in corn are grasshoppers and western bean cutworms.
"Western bean cutworms are beginning to lay eggs now in Nebraska, and should be scouted for now,” he says.
Western bean cutworm eggs are laid in masses on the upper half of corn plants. "After the eggs hatch, the cutworms move to the ear where they feed on developing grain,” Wright says.
To combat these pests, Wright says insecticides applications should be made shortly after the eggs hatch. As a general guideline, Wright says treatments should be made if 5% of the plants in the field have one or more egg mass.

Grasshoppers are another pest Wright has been seeing in parts of Nebraska.

"Treating grassy field borders and the edge of the field may be an economic control method to reduce damage to crops if grasshoppers are abundant,” he says.
Currently, the grasshoppers in Nebraska are about half-grown, Wright says. "As grasshoppers get larger they are harder to control with insecticides, so now would be a good time to check your fields and make a decision on whether to treat.”

Pests to Put on Your Calendar
Purdue University provides the Corn Scouting Calendar to aide farmers in knowing when to look for what pests.
For July, the calendar suggests scouting for:
  • corn rootworm
  • European corn borer
  • Japanese beetle
  • corn rootworm
  • armyworm
  • stalk borer
  • brown stink bug
  • grasshoppers
  • fall armyworm
  • two-spotted spider mite
  • cereal leaf beetle
  • corn leaf aphid
By consulting the Corn Scouting Calendar, you can learn more about each of these pests, along with the pests to scout for later in the season.
Be Prepared for Scouting
When scouting for pests, several items may be needed. Bill Bauer, an independent crop consultant in Ohio and Michigan, suggests having the following tools when you head to the fields:
  • Pollen hat
  • Safety glasses
  • Scouting guides
  • Weed control and insect guides
  • Field crop reference guide
  • Tape measure
  • Hatchet
  • Change of clothes
  • Something to drink

You can e-mail Sara Schafer at


This article appeared in the latest issue of AgWeb's Corn eNewsletter. To sign up for a free subscription, click here.

Back to news


Spell Check

No comments have been posted to this News Article

Corn College TV Education Series


Get nearly 8 hours of educational video with Farm Journal's top agronomists. Produced in the field and neatly organized by topic, from spring prep to post-harvest. Order now!


Market Data provided by
Brought to you by Beyer