Fall armyworm threat looms in Ohio

By Andi Anderson

This August, Ohio farmers and researchers began noticing a sharp increase in fall armyworm (FAW) populations across various counties.

Some areas reported no issues, while others saw a surge in FAW activity, with Van Wert County reporting the highest numbers at over 800 moths, with one trap catching 256 moths.

Fall armyworms are a growing concern for farmers with crops like corn, sorghum, small grains, and pasture grasses. The presence of FAW larvae in fields can lead to significant crop damage if left untreated.

While it is still too early to predict the full impact, experts expect that the number of larvae could increase toward the end of August.

Farmers are advised to closely monitor their fields, especially in counties with high FAW averages like Van Wert, Wayne, and Wood. Since the outbreak of fall armyworms in 2021, Ohio has implemented a statewide monitoring program to track their numbers and help farmers take action quickly.

Fall armyworms are easier to manage when they are smaller, and early detection is key to preventing significant damage.

Farmers should look for egg masses on plants and nearby structures. The larvae vary in color and are identified by an inverted white "Y" behind their heads. Scouting fields for these signs is crucial to controlling FAW populations before they grow larger and harder to manage.

For crops like corn and forage, timely insecticide applications can help control smaller caterpillars. Insecticides work best when applied early, before the larvae reach larger sizes, at which point they become harder to control. Continuous monitoring of crops is advised through the fall, especially in fields near harvest.

Farmers should take precautions such as early cutting of hay fields and monitoring regrowth for new infestations. While fall armyworms do not overwinter in Ohio, they migrate into the state from the South, and a long, warm fall could lead to a third generation of the pest.

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