By Dr. Robert Moon
They are back! Fall armyworms are marching across Texas and feeding in your turf areas and on many other plants. They are called armyworms because of the size of the infestations and the way they eat their way across an area. After hatching, the newly emerged larvae start immediately eating. The caterpillars range in color from shades of brown, to gray to green or yellow-green. Distinguishing characteristics are a whitish inverted i between the eyes and whitish strips on the head. They appear first on the tips of the grass blades and if not detected, they eat through the grass. Initial damage resembles drought but on closer inspection, you can tell the grass has been defoliated with only stems remaining and you can see the caterpillars.
To control, apply a liquid or granular turf insecticide that has armyworms on the label and can be purchased from any of the local garden shops. The liquid control can be applied with a hose on sprayer. The granular product can be spread with a fertilizer spreader. Products to look for include Ortho Bug B Gon (liquid or granular), Spectracide Insect Killer for Lawns (granular or liquid), Sevin (liquid or granular) or for organic control, apply Neem Oil or Bacillus Thurengiensis (BT). Follow all label instructions when applying. If these armyworms are eating your vegetable garden, make sure to use a product labeled for use on vegetables.
If damage is present, after treating, go ahead and fertilize to encourage recovery.
These armyworms eat and move through an area quickly, so be on alert!