October 16, 2009

Fall armyworm – Reports of activity in Hot Springs, AR
There are reports of fall armyworm in central Arkansas on some golf courses in the Hot Springs area.  Fall armyworm egg survival is high during periods of high and frequent rainfall similar to our weather pattern over the last month. If you have not recently scouted areas of your sod farm, golf course, or residential lawn it should be done soon.

Fall armyworms are caterpillars that cause damage by feeding on the leaves of green turf.  Larvae are white, yellow, or light green in color after egg hatch and they darken in color as they develop.  Mature fall armyworms are 1.5-inches long.  Fall armyworms can be identified by the presence of an upside-down Y marking on their head. Larvae can quickly (a few days) turn a green turf into a brown area by feeding on leaves across the area. This pest can be problematic until a hard frost in late October or November.

Scout several areas of your property to check for the presence of fall armyworms, especially in areas adjacent to pastures, or agronomic crops. Armyworms can be easily found by watering a square yard of turf with one gallon or water containing an irritant (1-2% soap or a pyrethrin insecticide). This will usually cause the pest to come to the surface within a few minutes making it easier to find the pest and get an accurate count on their number. This method does not work on soil insects such as white grubs or billbug larvae. If more than 1 mature larvae (>1 inch) or more than 2 immature larvae (< 1 inch) are present on average per square foot, then treatment is recommended.

Aaron Patton

More information on insecticides labeled for control can be found in

Homeowners: MP 144 – Insecticide Recommendations for Arkansas

Turfgrass Professionals: MP 144 – Insecticide Recommendations for Arkansas

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