When small, armyworms tend to be green, but they turn a tan to grayish color as they grow, with tan stripes and one orange stripe down their sides. Four pairs of fleshy prolegs in the midsection with a black triangle on the side of the feet distinguish the true armyworm from other armyworms.
Missouri’s last major infestation was in 2010. Bailey says the worms appear about every three to four years. “We were due for an infestation,” he said.
The MU Pest Monitoring Network has monitoring reports and information on scouting and identifying true armyworms at ipm.missouri.edu/pestmonitoring/taw.
Additional information is available in the MU Extension publication “Management of the Armyworm Complex in Missouri Field Crops” (G7115), available for free download at www.extension.missouri.edu/G7115.