Saturday, August 23, 2014

Diseases Appearing in Soybeans Says MU Extension Agronomy Specialist

Contact: Jill Scheidt, agronomy specialist
Headquartered in Barton County
PHONE: 417-682-3579

LAMAR, Mo. -- Jill Scheidt, agronomy specialist with University of Missouri Extension in Barton County, scouted fields north of Arcola on Aug. 20 for the MU Extension crop scouting program. Scheidt offers this advice from the field.


Corn in the area is at from 75 to 100 percent black layer.

Scheidt did observe corn earworms feeding on mature kernels.

“The corn earworms were moving slow and should move to other fields or end their lifecycle soon. There was not enough damage and it is too late to spray an insecticide,” said Scheidt.

Scheidt recommends a fungicide in the bin to prevent disease if a lot of kernels are damaged by corn earworm.


Soybeans are in the beginning bloom to beginning seed stages.

Scheidt observed grasshopper feeding was seen on leaves; threshold levels for foliage feeding insects are 20 percent defoliation during or after bloom. Hero, Warrior or Mustang Max are the recommended controls.

“No corn earworms were seen but should be scouted for in soybeans. They pose the biggest threat to second crop soybeans,” said Scheidt. Threshold levels are 1 per foot of row or when 5% of pods are damaged.

Septoria brown spot was seen south of Lamar.

“It is too late to spray a fungicide in order to prevent or control most diseases if soybeans are past the flowering stage. Fungicide applications made after the flowering stage or once the disease is present, usually only suppress the disease,” said Scheidt.

According to Laura Sweets, plant pathologist with the University of Missouri Extension, fungicides do not need to be applied unless favorable weather conditions for disease are present.

Sudden death syndrome, or SDS, was seen in irrigated fields in Lamar. “SDS is caused by susceptible varieties and wet conditions,” said Scheidt.

According to Jason Bond, plant pathologist with the University of Illinois, turning off irrigation is not a good option if soybeans are developing seeds, because the consequences of dry growing conditions without irrigation outweigh the effects of SDS.

“There is no rescue treatments for SDS, selecting resistant varieties is the best control option,” said Sweets.


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 to receive it a week earlier by telephone, contact the MU Extension Center in Barton County, (417) 682-3579.


Post a Comment

Let us know how you have been helped by this article or what you have learned from this story.

<< Home