Fall army worms rearing their ugly heads throughout the US and Nebraska

Many of you may recall the devastating outbreak of Fall army worms in Nebraska decades ago. Well, put your tray tables on the upright and locked position and fasten your seat belts! Egg masses (40 in one yard) have been found in Lincoln and moths are flying abundantly in Omaha. Feeding should begin in the next couple of days and continue for several weeks or longer.  They feed on  ryegrass, fescue, bentgrass and bluegrass. They normally are isolated to the southeastern region of the US and move north in storms. The abundance of weather events has brought them to Nebraska.

Image courtesy of Jody Green UNL

The reason that these pests are so newsworthy is that they feed in big numbers and cause lots of damage to lawns, marching across in “army infantry like” fashion, leaving dead plants in their wake. Prudent steps going forward are:

Inspect your lawn every other day, looking closely at the grass blades and crowns for feeding damage and the presence of small black/grey caterpillars. If 4-5 per square foot are found, mow the lawn to a 2 inch height and apply carbaryl or permethrin according to label directions. Dipel and spinosad are “organic’ options that are also effective. If granular formulations of these products are used, water the lawn lightly after application to wash the product off the leaf blades and down to the soil surface. Re-inspect every other day, and re-treat as necessary to keep the population under control. If damage is severe, reseeding/resodding may be necessary. See: https://grobigred.com/2019/08/14/lawn-renovation/

Images courtesy of Ben McGraw, Penn State University

John Fech
Horticulture Extension Educator at Nebraska Extension
John Fech is a horticulturist with the University of Nebraska-Lincoln and certified arborist with the International Society of Arboriculture. The author of 2 books and over 200 popular and trade journal articles, he focuses his time on teaching effective landscape maintenance techniques, water conservation, diagnosing turf and ornamental problems and encouraging effective bilingual communication in the green industry. He works extensively with the media to extend the message of landscape sustainability, making over 100 television and radio appearances each year.
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