Bluegrass billbug (Sphenophorous parvulus)

What do they look like?

The many common and hybrid types of Bermuda grass share a low-growing profile and fine-pointed leaves.

How do we know we've got them?

Billbug damage is often mistaken for drought stress or disease. Their hallmark damage shows up in summer as small (2-3 inch) dead patches of turf, which resemble the disease dollarspot. Left unchecked, they will spread to create large dead areas. These larger patches look like grub damage, but the root systems are still intact, so the turf will break off at the surface rather than roll up. To check for billbugs, do the tug test in the late spring: tug on some grass from the infected area. If it comes up easily and you see hollowed out stems filled with a substance resembling sawdust, your ills are billbugs. Poke around the area to find the fat larvae if you need more convincing.

How do they damage our lawns?

The bluegrass billbug will hollow out stems and crowns, feeding on both while leaving the turf to die. The first signs are scattered dead stems on the lawn followed by dead patches. Because there is only a shell of the plant left and the crown has been damaged, the plant cannot recover through watering or fertilizer.

How do we get rid of them?

The bluegrass billbug prefers highly maintained bluegrass and ryegrass lawns. If you suspect damage, do the tug test, but also set out traps to help with detection of movement and activity. Place small plastic cups in the ground, letting the adults fall in. Check these frequently as they will help you know when control will be necessary and effective. When the adults become active, an insecticide can control them before they lay eggs in the spring. You can also control larvae, but that has to happen in the summer. Some Perennial ryegrasses have inherent resistance to billbugs, but there is little information for bluegrasses.