Friday, May 03, 2013

Scouting Report May 1: Area Wheat Now Safe from Aphids but Cutworms are Showing up in Local Corn Fields

Contact: Jill Scheidt, agronomy specialist
Tel: (417) 682-3579

Jill Scheidt, agronomy specialist with University of Missouri Extension in Barton County, scouted fields in Barton and Lawrence County on May 1.

At that time, the flag leaf was out in most wheat fields and she did find aphids.

“If the flag leaf is present, aphids are no longer a concern,” said Scheidt. “If the flag leaf is not present in wheat threshold level for bird cherry oat and greenbug aphids are 9 aphids/ ft.”

According to Scheidt, the main concern in wheat after the flag leaf is present is disease. Powdery mildew and septoria continue to be seen but not at an economic level to spray a fungicide.

“It is economical to spray for fungus diseases in wheat when the disease is moving up the plant toward the flag leaf. The flag leaf accounts for 75% of grain fill,” said Scheidt.

Cutworm was seen in corn fields in Lawrence County above threshold level. Threshold level for black cutworm is 2-3 percent of plants damaged at or below soil level and when 6-8 percent of plants are damaged above ground level.

Black cutworm clip corn plants off at the growing point, killing the plant. Cutworm can clip many plants in one night. Black cutworm cause more damage when planting or emergence is delayed.

Scheidt says black cutworms should be scouted for up to the 4-5 leaf stage. 2.8 oz/a Mustang Max or 1.3 oz/ a Warrior II are recommended for black cutworms.


The weekly field scouting report is sponsored by University of Missouri Extension and Barton County Extension.

For more information on this scouting report, or to learn how you can receive it a week earlier by telephone, contact the MU Extension Center in Barton County at (417) 682-3579.


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