Army Worm Infestation

Army Worm Infestations

Outbreaks in Florida lawns are most likely from late summer through fall. Bermudagrass is a favorite, though St. Augustine and other turf grasses get eaten too. Caterpillars feed in groups, and young ones leave chewed blade tips with thin, clear patches.

How to Spot Armyworms Before the Whole Lawn Turns Brown

Armyworm damage tends to show up fast. A stretch of grass that looked fine on the weekend can look ragged and straw-colored a few days later, and the brown area often spreads outward as the caterpillars move toward green grass. Older caterpillars chew whole blades down, so the lawn can look as if it was mowed far too short in uneven patches.

Other signs worth checking:

• Birds gathering on one part of the lawn and pecking steadily at the grass
• Small green to dark pellets of droppings (frass) down in the thatch
• Striped caterpillars crawling across driveways and sidewalks, usually early or late in the day
• Gray-brown moths around porch lights at night, and fuzzy, tan egg clusters on walls, screens, eaves or light poles

A quick test: mix a couple of tablespoons of liquid dish soap into a gallon or two of water and pour it over a few square feet at the edge of the damage. Caterpillars hiding in the thatch usually crawl up to the surface within a few minutes. Try a few spots, since feeding is often patchy.

In Florida, armyworm outbreaks in lawns are most common from late summer into fall, and the season runs longer the farther south you go. Sunny St. Augustine and bermudagrass lawns are frequent targets. If the soap test brings up caterpillars, the steps on how to get rid of army worms are the next stop.