AgEBB-MU CAFNR Extension

David Burton
Civic Communications Specialist
2400 S. Scenic Ave.
Springfield, MO 65807

August 25, 2017

Field Crop Scouting Report
Scout for Podworms in Soybean

LAMAR, Mo. — Jill Scheidt, agronomy specialist with University of Missouri Extension, scouted fields near Arcola for the Aug. 9 crop scouting update.

Printed reports are sent out one week after the report to allow subscribers to phoned reports the full benefit of their subscriptions. Barton County MU Extension sponsors the field scouting report. For more information on the scouting report, or to learn how to receive the information earlier by telephone, contact the Barton County Extension Center at (417) 682-3579.


Corn ranged from the milk to soft dough stage.

"Some fields had quite a bit of corn earworm feeding in the tips. Corn earworms, also known as soybean podworms, were less than one inch long in these fields," said Scheidt.

Fields with completed pollination, look to have pollinated well.

"Gray leaf spot and southern corn rust was confirmed in last week's sample. Corn can benefit from a foliar fungicide if southern rust is present up to the brown silk stage," said Scheidt.


Soybeans ranged from the fourth trifoliate to beginning pod stage. No podworms were seen.

"Scout for podworms once soybeans begin to bloom," said Scheidt.

Threshold for podworm in soybeans are 1 per foot of row or when five percent or more of pods are damaged.

"Late planted and double crop soybeans are at greatest risk for podworm damage," said Scheidt.

Scheidt observed a few green cloverworms.

"They are primarily foliage feeders and unlikely to do significant damage. Threshold for any foliage feeding insect is 30 percent defoliation before bloom and 20 percent defoliation during or after bloom," said Scheidt.


Milo was in the boot to head stage; no sugarcane aphids were seen.

"Low numbers are likely due to timely rainfalls, some of which were heavy. Scout regularly by looking on the underside of leaves for small yellow aphids in clusters. If aphids are found, daily scouting is advised as populations can increase rapidly," said Scheidt.

Growth Stage specific thresholds for Missouri:


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Source: Jill Scheidt,(417) 682-3579

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