The GreenBee field almanac / Lawn life
Moths above.
A closer look below.
Follow the tropical sod webworm from a moth in the yard to a caterpillar beneath the grass. See how feeding leaves its mark—and why protection needs to reach the feeding stage.
Moths are the clue.
Moths can be a clue to tropical sod webworms. The larvae damage grass. Adult moths do not.
UF/IFAS · Tropical Sod Webworm ↗Reduced motion is on. The film waits for you to press Play.
A closer look at lawn life.
This film focuses on the tropical sod webworm, Herpetogramma phaeopteralis, in St. Augustinegrass. Reference photographs accompany illustrative footage and animation. Magnification, the animated emergence, and the treatment mechanism explain the story; they are not an identification key, an elapsed-time record, or a diagnosis of your lawn.
Egg photograph: Nastaran Tofangsazi, UF/IFAS. Larval stages and pupa photograph: James Kerrigan, UF/IFAS. View the photographic references ↗
Acelepryn Xtra is shown for its systemic and residual activity against listed pests. Protection depends on application and label directions. No fixed protection interval or recovery timeline is promised.
Read the complete explanation
- Moths are the clue. Seeing small moths lift from your lawn? They can be a clue to tropical sod webworms. But the moths aren’t chewing your grass. Their caterpillars are.
- A sheltered place by day. During the day, adult moths shelter in shaded shrubs and other vegetation. Finding them there is a reason to take a closer look at the nearby lawn.
- Another generation begins. Female moths lay clusters of eggs on grass. Those eggs can hatch within days, depending on conditions, bringing a new generation of hungry caterpillars.
- Hidden in the thatch. Look beneath the leaves. This fibrous layer is called thatch. Larvae shelter here during the day, then come out to feed at night.
- Watch what happens to the blade. Watch the edge of the blade. Older caterpillars chew away sections of grass, leaving the leaves ragged and shortened.
- The damage you see above. As feeding injury builds, the lawn can develop irregular yellowish or brown patches. Other lawn problems can look similar, so inspection matters.
- The cycle continues. The caterpillars eventually become pupae, then adult moths. Different stages can overlap, allowing more feeding larvae to appear as the cycle continues.
- Protection at the feeding stage. Acelepryn Xtra moves into the plant and controls feeding larvae. Its residual activity helps protect against later outbreaks. Protection depends on proper application and label directions.
- A closer look. A clearer plan. Green Bee can inspect your lawn and explain the treatment.
Sources behind the story.
- UF/IFAS · Tropical Sod Webworm ↗Larval appearance, daytime shelter, night feeding, and visible injury.
- University of Minnesota Extension · Thatch ↗Definition and position of the thatch layer.
- Texas A&M AgriLife Extension · Tropical Sod Webworm ↗Additional regional reading.
- Texas A&M AgriLife · Moths and lawn damage ↗Regional observations of notched blades, irregular brown patches, and inspection.
- Syngenta · Turf caterpillar solutions ↗Acelepryn Xtra systemic movement and residual caterpillar control. Duration depends on the application.
- Acelepryn Xtra · Current label ↗Product-specific use directions and restrictions; EPA registration 100-1680.
Biology: university Extension. Treatment: manufacturer documentation and label. Sources checked September 24, 2026.