Billbug Damage in Lawns
Searcy, Ark. –
Billbugs are major pests of turf across the U.S. The four pest species found in the country are the Bluegrass billbug, Hunting billbug, Denver billbug, and Phoenician billbug, all belonging to the genus Sphenophorus. The Hunting Billbug (S. venatus vestitus Chittenden) is the most common in the southern U.S.
Identifying Adult and Larval Billbugs
Adult billbugs are reddish-brown to black weevils, measuring between 1/2″ and 3/4″ (13-19 mm) in length. They are characterized by a "snout" or "bill." The adult Hunting Billbug can be distinguished by a "Y" marking on the pronotum, surrounded by parentheses.
Billbug larvae are C-shaped grubs, white with brown head capsules. Unlike true white grubs, Billbug larvae do not have legs.
Billbug Feeding Behavior and Damage Signs
Young larvae burrow into grass stems, feeding on internal plant material and leaving sawdust-like frass (insect waste). During a "tug" test, damaged grass pulls away easily from the thatch, often revealing frass at the damaged end or falling from the stems.
Life Cycle and Seasonal Activity
Billbugs overwinter as larvae and emerge in the spring. In southern regions, they can produce two generations annually, with the second generation emerging in early fall.
Factors That Affect Billbug Damage
Billbug damage worsens under improper fertilization and irrigation. However, proper maintenance can mask light infestations. Early infestations may resemble dollar spot disease, but severe infestations result in large dead patches. Using resistant cultivars—such as some varieties of Bermuda and Zoysia grass—provides long-term cultural control.
Biological Control Options
Entomopathogenic nematodes, such as Steinernema carpocapsae and Heterorhabditis bacteriophora, can be applied at a rate of 1 billion juveniles per acre, followed by irrigation.
Chemical Control Options
Chemical control involves using surface residual sprays for adults and white grub treatments for larvae. Homeowners in Arkansas can use the following white grub insecticides:
- Carbaryl (various brands)
- Chlorantraniliprole (Acelepryn, GrubEx1)
- Clothianidin (Arena)
- Clothianidin + Bifenthrin (Aloft)
- Halofenozide (Mach 2)
- Imidacloprid (Merit, Advanced Lawn Grub Control)
- Thiamethoxam (Meridian)
- Trichlorfon (Bio Advanced)
By Sherri Sanders
County Extension Agent - Agriculture
The Cooperative Extension Service
U of A System Division of Agriculture
Media Contact: Sherri Sanders
County Extension Agent - Agriculture
U of A Division of Agriculture
Cooperative Extension Service
2400 Old Searcy Landing Road Searcy AR 72143
(501) 268-5394
ssanders@uada.edu
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