Sod WebWorm

Common species in New Jersey include the bluegrass webworm
[Parapediasia teterrella (Zincken)] and the larger sod webworm
[Pediasia trisecta (Walker)]


SWW chew off leaves and stems just above the grass crown. Healthy well-maintained turf will often tolerate and recover from this scalping. However, weak or drought-stressed grass may be killed by sun-exposure of the crowns. Damage begins as general thinning, followed by small patches of brown, closely cropped grass. A close look will reveal the typical silk-lined SWW tunnels, often with clumps of pinhead-sized, green fecal pellets around the mouth of the burrows. In severe infestations,the scattered patches may coalesce into large irregular areas.

Because most SWW species don’t feed on grass roots, the damaged grass remains firmly anchored.Damage is most common in sunny sites during hot, dry periods.Early symptoms of damage may be masked by dormancy in drought-stressed grass, but this grass will not recover after rains. Flocks of birds probing in the grass may indicate SWW infestation but the birds may also be feeding on other insects.




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