Armyworms are destroying lawns

Q: I guess I have a bad infestation of armyworms. They ate an acre of my lawn in a few days. Can you give me some advice on what to use to get rid of them?

• Dave from Boardman

A: Dave is not alone. Fall armyworms have been wreaking havoc on lawns, pastures, hayfields and other crops throughout the Mahoning Valley — and across Ohio.

These 1- to 1.5-inch worms vary in color, with most having a gray-green look from above, with cream to yellowish stripes from end to end. They are green on their undersides.

There is a yellowstriped armyworm, but that is not the one we are seeing here in Ohio and throughout the Midwest.

Large populations of these insects occur every few years, with this one being linked to storms that covered most of Ohio during the first week of August. Our entomologists at OSU tell us the adults can travel via the jetstream and move 500 miles in just a day. When their journey ends, they find place to lay their eggs.

They begin laying eggs (100 to 500 in a mass) on limbs that overhang turf (or other suitable host plants for their larvae). Within seven days, these ferocious eaters hatch and begin marching through host plants and destroying nearly everything in their path. If there is not enough plant food, the large ones eat the smaller ones so they can pupate into an adult moth.

The biggest problem in lawns is loss of the turf. Once the fall armyworms eat all of the plant parts above the ground, they leave the crown. The crow is the growing point for the roots and leaves. The crown can be damaged or killed completely on hot, sunny days. Then, the turf needs replaced completely.

The good news is — this does not happen every year. The moths do not overwinter in the Mahoning Valley.

So, what to do? When it gets so bad so quickly (similar to the photo of a completely brown lawn that Dave sent), a chemical application may be the only hope at this point.

Frankly, it may be too late. Our experts state that irrigation after a chemical application will be the best thing to keep plants from dehydrating and dying.

For more details about the fall armyworms invading Ohio and some control options are at http://go.osu.edu/armyworms.

Please note that pesticides should be used as directed on the label. Users must read and follow all label directions.

Barrett is the Ohio State University Extension educator for agriculture and natural resources in Mahoning County. Call the extension office hotline, 330-533-5538, 9 a.m. to noon Mondays and Thursdays to submit your questions.


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