Be on the lookout! Armyworms are here! Not only have I been getting reports of armyworms across Pottawatomie County, but across all eastern Oklahoma. The fall armyworm, Spodoptera frugiperda, is a common pest of alfalfa, bermudagrass, sorghum, corn, wheat and rye grass and many other crops in Oklahoma and the southern Great Plains. Larvae of fall armyworms are green, brown, or black with white to yellowish lines running from head to tail. A distinct white line between the eyes forms an inverted “Y” pattern on the face. Four black spots aligned in a square on the top of the segment near the back end of the caterpillar are also characteristic. Armyworms are very small (less than 1/8 inch) at first, cause little plant damage and as a result often go unnoticed. Full-grown larvae are about 1 to 1 1/2 inches long. Given their immense appetite, great numbers, and marching ability, fall armyworms can damage entire fields or pastures in a few days.