AgEBB-MU CAFNR Extension

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

July 21, 2017

Field Crop Scouting Report
Scout for Insects in Soybean and Milo

LAMAR, Mo. - Jill Scheidt, agronomy specialist with University of Missouri Extension, scouted fields north of Irwin and near Verdella for the July 12 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 finished pollinating and ranged from the blister to milk stage.

"Pollination looked to be successful, with all kernels except the tip filled. Japanese beetles are not a threat to corn finished with pollination," said Scheidt.

Threshold for Japanese beetle in pollinating corn is three or more beetles per ear, clipping green silks to less than one-half inch.

"I have not seen many Japanese beetles in row crops this year, even though trap numbers have been high as usual," said Scheidt.


Soybeans ranged from third trifoliate to beginning pod stage. Scheidt observed a small amount of Japanese beetle foliage feeding on all stages. Threshold for Japanese beetle and any foliage feeding insect is 30 percent defoliation before bloom and 20 percent defoliation during or after bloom.

Scheidt observed Yellow Striped Armyworm, which are black in color, with a yellow stripe along their side; in soybean fields.

"They are primarily foliage feeders and have been seen in soybean fields," said Scheidt.

Scheidt advises scouting for soybean podworm in blooming soybeans by vigorously beating plants together and scouring the ground for larvae. Threshold for soybean podworm is 1 per foot of row or when 5-10 percent of pods are damaged.

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


Scheidt recommends scouting milo weekly for sugarcane aphid, by looking on the underside of the leaves, for small, yellow aphids.

"If aphids are found, scout daily as populations can increase rapidly to threshold level, which varies depending on crop stage," said Scheidt.

A guideline threshold set by the Sorghum Checkoff is 50 aphids per leaf, infesting 25 percent of plants. "Damaged plants" foliage turns reddish color and leaves eventually turn brown on the edges.

Sugarcane aphid can kill the plant or cause heads not to fill. The younger a plant is when infected, the more yield damage caused. Sivanto and Transform are recommended insecticides," said Scheidt.

Growth Stage specific thresholds for Missouri:

Source: Jill Scheidt,(417) 682-3579

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