Like its namesake military force, Armyworms can strike anywhere and become harder to control the larger they grow, however its name is derived from its feeding habits. Armyworms will eat everything in an area and once the food supply is exhausted the entire “army” will move to the next available food source, feeding and moving stealthily during the night, hunkering down beneath fallen debris during the day.
The Armyworm is actually the caterpillar life stage of a moth, and grows to about 1½” long. Pale green when first hatched, they change to olive green with a white stripe later on in the season, eventually morphing into brown moths sporting a white spot on each wing.
The Armyworm causes damage similar to that of sodworms, but it is more scattered and not confined to patches. The damage usually moves in from the edges and often proceeds in a relatively straight line as the Armyworms march across the lawn.
Preventive and organic control measures include
- Raking up fallen debris to eliminate daytime hiding places
- Encouraging birds to visit by setting out feeders, birdbaths or nesting material in the area where the worms are feeding
- Attracting predatory wasps to control the Armyworms by planting dill, fennel, coreopsis and brightly colored flowers near the feeding areas
- Spraying Bacillus thuringiensis, an organic control for caterpillars, in the late afternoon or early evening hours when you see the first signs of armyworm damage in your garden. Bacillus thuringiensis (or Bt) is actually a bacteria and is safe to use around children and pets. There are also numerous chemical sprays available to control armyworms.
Many turfgrass managers use pyrethroids for Armyworm control.
Because they are most active in the fall, it is time to set up your reconnaissance mission now, becoming familiar with the health of your lawn or garden. If these measures are not sufficient to control the advancing army, enlist the aid of a professional pest control company.












