Monday, August 11, 2014

Pest Levels Low in Corn and Soybean Fields

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 northwest of Liberal on Aug. 6 for the crop scouting program. Scheidt offers this advice from the field.


Corn is in the dent to black layer stages. “Black layer is when corn has reached physiological maturity, about 20 days after the dent stage. Black layer can be identified by breaking the ear in half and looking for the milk-line, a dark yellow line that gradually forms closer and closer to the cob,” said Scheidt.

According to Mississippi State University Extension, when black layer is reached, irrigation should be shut off. Potential kernel weight is only about 75 percent complete at the dent stage. Irrigation is still needed at this stage to fill kernels.


Based on her scouting, Scheidt says soybeans are in the 6 to 7 trifoliate and podding stages.

According to Laura Sweets, state pathologist with University of Missouri Extension, fungicide application timing for soybean foliar disease management should begin at pod initiation. This is when 3/16 inch long pods are at one of the four uppermost nodes on the main stem with a fully developed trifoliate leaf node.

“Fungicide applications should only be made if favorable conditions, such as wet, humid weather occur during this stage,” said Sweets.

Scheidt observed less than one percent pod damage from pod worm and bean leaf beetle in podding soybeans. Threshold level for pod worm is 1 per linear foot and when five percent of pods have damage. Second crop soybeans are at greater risk for pod worm damage.

“Do not misidentify green clover worm with pod worms, green clover worm carry a fungus that kills pod worms. Green clover worm and pod worm are similar in color but can be differentiated by counting the number of abdominal pro-legs.  Green clover worm have three abdominal pro-legs and pod worms have 4 abdominal pro-legs,” said Scheidt.


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.


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