Armyworms Begin Invading Plants, Crops in Ozarks

(Galena, MO) -- Over the last few days, there have been reports of crop-damaging armyworms in at least five Ozarks counties.

Agronomy specialists have been closely watching the insects as they've already done significant damage to crops and plants in northern Arkansas.

Tim Schnakenberg, an agronomy specialist with MU Extension, says he's received reports of armyworms in Barry, Cedar, Dade, Stone and Christian counties in the last few days.

The University of Missouri Extension says the moth activity has been noticed on fescue, bermudagrass, wheat and corn. Others have been found in monitoring traps over the last month.

The larvae have a greenish-brown body, nearly hairless, with two orange stripes along each side. The head is brown with honeycomb markings.

According to Schnakenberg, once the moths move into an area, they lay their eggs and it may take two to three weeks for the young larvae to start doing damage. It only takes the larvae five to seven days to grow from one-half inch to 1.5 inches in length.

"The economic threshold for spraying this pest is when 25 percent or more of the plants are being damaged.  If the outbreak elevates to a high level, armyworms can consume a large amount of foliage and stunt the crop. Check the seedlings and the whorls for leaf feeding," said Schnakenberg.

They're night feeders, so the best time to look for them on your plants is either dusk or dawn. As they grow older, larvae will do more daytime feeding.

Information on sprays and recommendations for treating armyworms

Monitor insect activity in Missouri through the Missouri Pest Monitoring Network