Missouri hay growers and livestock producers should be on the lookout for true armyworms in fields and pastures, says Wayne Bailey, entomologist with University of Missouri Extension. He advises trying to get ahead of the pest while it’s still in the larvae stage.

Calls about armyworm damage, mostly from southwestern and east-central Missouri, started coming into Bailey’s office about two weeks ago. Most reports concerned fescue fields.

Immature worms feed at night, so scouting at dusk and early morning will be more successful than at mid-day. “You must get down into the grass to find them,” says the entomologist. “They start feeding down low and work up. Just looking at the top of the grass, you will miss them.”

The economic threshold for spraying is 7-15 larvae/sq. yd. “With the value of the hay crop, it may pay to use the lower number this year.”

For more on the pest, view the Missouri Extension factsheet: “Management of the Armyworm Complex in Missouri Field Crops.”

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