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Adult moths are 3/4 inch (1.9 cm) long and have an appendage
in front of the head resembling a snout. The moth holds its wings
close to and over its body at rest, giving it a slender appearance.
When disturbed, lawn moths make a short flight close to the grass.
Sod webworms are the larvae of lawn moths. The larvae are cream colored,
3/4 inch (1.9 cm) long, and have a distinctive double row of brown
or black spots down their backs, located at the base of brown bristles.
The spots, bristles, and smaller, more slender size distinguish them
from cutworms and armyworms.
All turfgrass species, especially annual
bluegrass (a common weed in turf), creeping
bentgrass, and Kentucky
Damage appears as irregular patches of brown or bare areas. Leaves
are chewed or missing. There is no feeding damage to roots. Damage
is more severe on drought-stressed turf.
Look for larvae from early summer to mid-fall. Perform a drench
test to find slender, cream-colored larvae. Look for whitish
or brownish moths flying close to the grass when disturbed.
Reduce thatch and follow recommended irrigation and fertilization
practices. If more than 15 larvae per square yard are found,
you may need to treat the area. An application of Bacillus thuringiensis or
other safe product may reduce populations. Beneficial
nematodes may also be effective if applied when larvae are
For more information on lawn insects, refer to:
Pest Notes: Lawn Insects