If your lawn has brown, thinning patches in midsummer that don't green up after watering, the cause may be hiding inside the grass stems. Around your South Orange home, billbugs are one of several lawn insects that can cause this kind of damage, and they're among the hardest to spot. The trouble with billbugs is that their damage looks like so many other lawn problems that they often go unnoticed until the lawn is already hurting. Below, we'll cover what billbugs are, how to recognize them, how to confirm the damage and what helps prevent it. If you're seeing insects you can't identify around your yard, our outdoor pest control team can take a look.
What Billbugs Are
Billbugs are a type of weevil, a beetle with a long snout. The bluegrass billbug is well known in cool-season lawns of the Northeast, and a few related species also feed on turf.
- Adults. Small, gray to black beetles with a downward-pointing snout. They're slow, and they often play dead when touched.
- Larvae. Small, white, legless grubs with a brown head, usually curved into a C shape. They're smaller than the white grubs found in lawn soil.
Adults spend the winter in leaf litter and thatch, often near the edges of lawns. In spring, they become active and are often seen walking across driveways, sidewalks and patios on warm days. Females chew small holes in grass stems and lay eggs inside. The larvae feed down inside the stem, then move to the crown and roots as they grow.
The Problems Billbugs Cause
- Damage shows up late. Larvae feed out of sight for weeks before the lawn shows any change.
- It looks like drought. Small brown spots grow into larger irregular patches during the heat of summer, just when lawns are stressed anyway.
- It's easy to misdiagnose. Billbug damage is often blamed on dry weather, disease or white grubs, so the real cause goes untreated.
- It can come back. If conditions don't change, the same areas can be damaged again the next year.
How To Confirm Billbug Damage
Try the tug test. Grab a handful of grass at the edge of a brown patch and pull gently. If billbugs are feeding, damaged stems will break off right at the base and come out easily. Look at the broken ends. You'll often see fine, light-colored, sawdust-like material packed inside, which is waste from the larvae.
This sets billbugs apart from white grubs. With grubs, whole sections of turf peel back like carpet because the roots have been eaten, and you'll find larger C-shaped grubs with legs in the soil. Our guide on what causes grubs in lawns covers those. Chinch bugs and sod webworms cause other kinds of lawn damage with their own signs.
Are Billbugs Harmful?
Not to people, pets or your home. Billbugs don't bite, sting or come indoors to breed. You may find a few adults on a patio or near a door in spring, but they're simply passing through. They don't eat ornamental plants, wood or stored food, so there's nothing in your home for them.
The harm is to your lawn. Billbug damage kills grass plants at the crown, so affected areas often need to be reseeded or patched rather than simply watered back to health. Lawns that are already stressed by heat, drought or heavy thatch tend to suffer the most.
How To Prevent Billbug Damage
- Watch for adults in spring. Weevils crawling on paved areas near the lawn are an early warning.
- Water deeply during dry spells. A well-watered lawn can outgrow light feeding.
- Manage thatch. Heavy thatch gives adults shelter. Dethatch or core aerate when needed.
- Mow at the right height. Taller grass has deeper roots and handles stress better.
- Choose resistant grass when reseeding. Some perennial ryegrass and tall fescue varieties contain beneficial fungi called endophytes that make them less appealing to billbugs. Ask your seed supplier.
- Repair damaged areas. Rake out dead grass and reseed in late summer or early fall.
For timing and product choices on lawn treatments, a lawn care professional or your county office of Rutgers Cooperative Extension can give advice specific to your grass type.
When To Call A Professional
If brown patches keep coming back and you can't tell why, it's worth having someone look. EcoFusion doesn't provide lawn care or fertilization. Our NJ DEP-licensed technicians can inspect your property, help identify the insects you're finding and recommend the right next step, whether that's a lawn specialist or a plan for pests that are moving toward your house. We use Integrated Pest Management and EPA-registered, eco-safe products.
Billbugs are small, but they can do real damage to a lawn before anyone notices. A quick tug test on the next brown patch can tell you a lot about what's going on at your South Orange home.