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Is that Brown Grass Just Distressed or Being Devoured? 07-24-13 | News

Is that Brown Grass Just Distressed or Being Devoured?

Sod webworm larvae vary in color from gray or light green to tan or brown. A physical characteristic that sets them apart from other species is their spotted backs. These larvae will grow to reach a length of approximately 1 inch.

Sometimes what is diagnosed as sod distress is actually caused by larvae damage. Proper identification is important for effective detection and control.

One common larvae that can be the culprit is the sod webworm, which typically attacks Kentucky bluegrass, perennial ryegrass, fine fescue and bentgrass through late September. According to Dr. Bobby Walls, turf product development manager for FMC Professional Solutions, areas of damaged turf first appear as small brown patches. These patches will often run together causing large and irregular-shaped damaged areas.

The pests burrow in tunnels in thatch during the day and emerge at night to feed. These feeding habits explain how serious damage often occurs before it is noticed. Blades are eaten back unevenly and may even be completely stripped off in patches.

A disclosing solution of two tablespoons of liquid detergent in a gallon of water sprinkled evenly over a square yard of turf will irritate the worms causing them to crawl to the surface. The recommended treatment threshold for these pests is typically 10 to 15 worms per square yard.

To control sod webworm, FMC Professional Solutions offers two products: Talstar???(R)???AE???? Professional insecticide for liquid applications and Talstar???(R)???AE???? XTRA featuring Verge• for granular applications.