PHILADELPHIA -Turf managers can tell what type of larvae is invading their turf by the unique physical characteristics of the damage caused. Sometimes larvae damage can be mistaken for disease or distress, so it’s important to know the differences between typs of larvae for effective detection and control.

One common larvae, the sod webworm, typically attacks Kentucky bluegrass, perennial ryegrass, fine fescue and bentgrass through late September. Dr. Bobby Walls, turf product development manager for FMC Professional Solutions, offers the following information about it:

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.

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. The nighttime feeding habits of the sod webworm explains how serious damage often occurs before it is noticed. Blades are eaten back unevenly and may even be completely stripped off in patches. Another common indicator is large flocks of birds gathering on the turf area to feed.

Control and Detection Tips

A disclosing solution (soap flush) technique is a useful tool for monitoring and detecting these pests. Sprinkle a mixture of two tablespoons of liquid detergent and a gallon of water evenly over a square yard of turf. The soap will irritate the worms causing them to crawl to the surface. The recommended treatment threshold for these pests is typically 10-15 worms in a square yard, after observing obvious damage to turf.

(Images, sod webworm, above; webworm damage, right. Courtesy FMC Professional Solutions)

Talstar Professional insecticide for liquid applications:

* Provides long-lasting residual control

* Non-irritating and non-staining

* Contains no odorous or plant-damaging solvents

* Leaves no unsightly residues and causes no phytotoxicity

* Compatible with other products so it works effectively for flexible tank mixing

 Talstar XTRA featuring Verge for granular applications:

* Provides long-lasting residual control

* Formulated with zeta-cypermethrin for extra speed

* The Verge granule is uniform in size and shape resulting in a more consistent, dependable barrier of protection

* Odorless and dust-free

For more information on FMC and its products, visit or FMC Turf Wire. Follow @FMCturf on Twitter.