Soybean Pod Worms in Area Fields, Can Impact Yields

LAMAR, Mo. – Soybean fields in southwest Missouri continues to receive timely rain and pods are beginning to fill according to Jay Chism, agronomy specialist with University of Missouri Extension.

“Unfortunately, soybean pod worms are also feeding on several soybean fields in and around Barton County,” said Chism. “The damage varies from field to field so it is very important to get out and scout for pod worm damage.”

Soybean pod worms and corn earworms are the same insects.

Although more commonly a pest of corn, when abundant, the corn ear worm may also feed on soybeans, where they are routinely called a soybean pod worm.

According to Chism, treatment is justified when leaf defoliation reaches 20 percent from bloom to pod fill or when larval numbers exceed one per foot of row and 5 percent or more of pods are damaged.

“It is important to look at your fields to determine if you have significant numbers of pod worms present,” said Chism.

If the larvae present are large (from 1.25 to 1.5 inches) then the larvae are probably getting ready to change lifecycles or pupate. At that time feeding damage will no longer occur.

“If pod worms are small and pod damages are near threshold levels, an insecticide application is recommended,” said Chism. “As with any input cost, yield potential of your fields should also be considered.”

For more information on this scouting report or how you can receive it by telephone each week, contact the MU Extension Center in Barton County at (417) 682-3579.

Several images of soybean pod worms can be found on the Barton County Extension website at http://extension.missouri.edu/barton.

These weekly field crop scouting reports are sponsored by MU Extension in Barton County and the Barton County Soil and Water Conservation District.