AgEBB-MU CAFNR Extension

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

August 18, 2017

Field Crop Scouting Report:
Continue Scouting for insects in Soybean and Milo

LAMAR, Mo. — Jill Scheidt, agronomy specialist with University of Missouri Extension, scouted fields along 126 and 43 highways near Nashville for the August 2 crop scouting update.

Printed reports are sent out two weeks 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 soft dough to one-quarter milk line.

"To identify how close to black layer corn is, break a corn ear in half and observe the cross-section of the top half of the ear," said Scheidt.

There will be a dark yellow line, this is the milk line, on the kernel that starts at the end of the kernel. As corn matures, the milk line moves toward the cob. Black layer, or maturity, occurs about 20 days after the dent stage.

If conditions are favorable, irrigation may not be needed after three-fourths milk line. Under hot, dry conditions, producers may benefit from watering until black layer.

Scheidt observed possible southern rust on corn in the dent stage. A sample has been sent to the MU Plant Diagnostics lab for confirmation, and an update will follow.


Soybeans ranged from second trifoliate to pod.

"Foliage feeding pressure from insects was low," said Scheidt. Threshold levels are 30 percent defoliation before bloom and 20 percent defoliation during or after bloom for any foliage feeding insect. No pod worms nor pod damage was found.

"Double crop and late planted soybeans are at the highest risk for pod worm damage. Scout for pod worms once soybeans reach the bloom stage," said Scheidt.


Milo ranged from flag leaf to head.

"A few more sugar cane aphid were seen than last week; numbers ranged from 10-20 aphids per plant," said Scheidt.

The threshold level for sugarcane aphid in boot to head stage milo is 500 per plant and two dead leaves or from head to maturity stage milo is 750 per plant and 2-3 dead leaves.

Growth Stage specific thresholds for Missouri can be found at

Source: Jill Scheidt, (417) 682-3579

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