MU Extension's centennial

On May 8, 2014, University of Missouri Extension celebrates 100 years of extending university-based research and knowledge beyond the campus into all 114 Missouri counties. In doing so, MU Extension has strengthened families, businesses and communities.


Weekly Crop Scouting Report 

Low levels of insects popping up in crop fields

This article is available as a PDF or Audio message.

Jill Scheidt, agronomy specialist with University of Missouri Extension in Barton County, scouted fields northeast of Lamar near Hwy. A and Hwy. EE on July 16.

Corn Fields
Corn is in the milk stage and corn earworms were seen feeding on kernels. “In one field I was finding one earworm in 5 out of 10 stalks, but in the majority of fields, one or no earworms every 10 stalks,” said Scheidt.

According to Wayne Bailey, state entomologist with University of Missouri Extension, there is no recommended threshold level; insecticide treatments are not economical because multiple applications are needed to obtain effective control.

“Corn earworms cause less than one percent yield loss because they feed on the tip, where the kernels don’t always fill,” said Bailey. Bailey suggests the following best management practices: early planting, selecting BT varieties with corn earworm resistance and varieties with tight husks.

According to Laura Sweets, state pathologist with University of Missouri Extension, fungicides are most profitable when disease or weather conditions favoring disease and disease susceptible varieties are present. “The optimum time to apply fungicides is from tasseling to the blister stage in corn,” said Sweets.

Soybeans Fields
Soybeans were in the first trifoliate to bloom stage. “I saw bean leaf beetle, blister beetle, grasshopper and Japanese beetles feeding but not at threshold levels,” said Scheidt.

Threshold levels for all foliage feeding insects are: 30 percent defoliation before bloom and 20 percent defoliation during and after bloom.

“Defoliation refers to the whole plant, so the whole plant must have 20 or 30 percent defoliation,” explains Scheidt.


Links to other resources:

Lodged corn

Soybean insects

VIDEO: A video about scouting for Armyworms can be viewed at:

"Crop Nutrient Deficiency and Toxicities"

Previous 2014 Crop Scouting Reports

“Managing Nitrogen in Wet and Dry Years” by Peter Scharf

MU Extension Corn Insect Pests Diagnostic guide

MU Extension publication G7112, Black cutworm guide

Corn freeze damage

Spring freeze injury

Frost freeze to corn and soybeans

MU Extension publication M171, 2013 Missouri Pest Management Guide

To receive the 2014 weekly scouting reports, print the 2014 Crop Scouting Enrollment Form (PDF), complete and return with payment to Barton County Extension, 801 E 12th, Lamar, MO 64759.

Crop scouting is an essential part of integrated pest management (IPM). Scouting programs are designed to protect and maximize crop yield and quality while minimizing the risk associated with pesticide use.  Each week, extension agronomy specialists and agronomy assistants scout fields in Barton County and then report their findings through an automated phone service and email message. The message will go out to everyone signed up for the program.

The cost of the program is only $35 per phone number, $95 for three numbers, and $30 per phone number for those with 4 or more. For more information about the program, call the Barton County Extension Center at 417-682-3579.


Popular extension publications

MU Extension publication G427, 2011 Cash Rental Rates in Missouri
MU Extension publication G302, 2009 Custom Rates for Farm Services in Missouri
MU Extension publication G6201, Vegetable Planting Calendar