Turfgrass-Billbug

Includes
Bluegrass billbug (Sphenophorus parvulus)
Denver billbug (S. cicatristriatus)

Hunting billbug (S. venatus)

Phoenician billbug (S. phoeniciensis)

Pest description and crop damage Adults are about 0.375 inch long, black, with a distinct snout. They lay eggs in late spring. Larvae are white with a brown head, no visible legs, and about 0.25 inch long when mature (much smaller than Japanese beetle and European chafer larvae). Larvae generally reach damaging size by midsummer. Larvae feed on grass roots. Damage often shows up as irregular patches of drought-stressed turf that is not anchored or rooted to the soil. Kentucky bluegrass and annual bluegrass is most commonly attacked by billbug larvae. However, tall fescue, perennial rye, and chewings fescue are also susceptible. Billbugs classically cause problems in eastern Oregon, central Washington and Idaho-especially around Ontario-Baker City and Boise-Twin Falls-and also occasionally from La Grande into the Columbia Gorge. More recently billbug damage has been observed in the Portland and Eugene, as well as the Seattle/Tacoma areas.

Biology and life history Bluegrass billbugs overwinter as adults. Eggs are laid on grass stems in May or June and hatch in about 2 weeks. As the larvae mature, they move from the crown of the plant into the soil where they feed on roots. There is one generation per year. The Denver and hunting billbugs have a similar life cycle but may lay eggs for a longer period of time resulting in larvae that overwinter in the soil. Damage from these species can occur much earlier in spring than damage from bluegrass billbug. Perennial ryegrasses, fine fescues, and tall fescues with high levels of endophytic fungi are resistant to billbugs.

Scouting and Action Threshold Scouting for billbugs should begin in the early summer (June and July) before damage occurs in the summer months. Scout in the top 2 inches of the soil using a shovel. The action threshold for well-maintained turfgrass is 10 to 20 larvae per sq ft.

Management-biological control

  • beneficial nematodes-Read label carefully for application procedures, timing and appropriate soil temperatures for best efficacy.

Management-chemical control: HOME USE

Treat the entire lawn, not just affected areas. Spring applications when adults first become active may prevent larval populations from building to damaging levels. Do not permit children or pets on the treated lawn until it has been watered to wash the insecticide into the turf and the grass is completely dry. Most insecticides are toxic to bees exposed to direct treatment or to residues on blooming weeds/ flowers in lawns: mow and remove clippings prior to applying insecticides.

  • azadiractin (as a mix with pyrethrins)-Some formulations are OMRI-listed for organic use.
  • bifenthrin (may be a mix with other active ingredients)
  • carbaryl
  • chlorantraniliprole
  • deltamethrin
  • fenvalerate
  • gamma-cyhalothrin
  • imidacloprid
  • lambda-cyhalothrin
  • permethrin
  • plant essential oils (clove, mint, peppermint, etc.)-Some formulations are OMRI-listed for organic use.

Management-chemical control: COMMERCIAL USE

Where the label allows, treat the entire turfgrass stand, not just affected areas. Some active ingredients target adults, while others target larvae; choose an active ingredient compatible with the treatment timing. Spring applications when adults first become active may prevent larval populations from building to damaging levels. Do not permit children or pets on the treated turfgrass until it has been watered to wash the insecticide into the turf and the grass is completely dry. Most insecticides are toxic to bees exposed to direct treatment or to residues on blooming weeds/ flowers in lawns: mow and remove clippings prior to applying insecticides.

  • azadiractin (Azaguard Botanical Insecticide/Nematicide, Neemix 4.5 IGR)-Some formulations are OMRI-listed for organic use.
  • Beauvaria bassiana GHA (Botanigard ES, Botanigard 22WP)-Some formulations are OMRI-listed for organic use.
  • beta-cyfluthrin (Tempo SC Ultra Insecticide)-Not for use on golf course turf.
  • bifenthrin (Talstar S Select Insecticide)-Restricted use. Apply at 0.05 to 0.1 lb ai/A. PHI 30 days. REI 12 hr. Bifenthrin is highly toxic to bees and other pollinators exposed to direct treatment or residues on blooming crops or weeds. Do not apply bifenthrin or allow it to drift to blooming crops or weeds if bees or other pollinating insects are foraging in the treatment area. Extremely toxic to fish and aquatic invertebrates. Do not apply if rain is expected within 12 hr or whatever time is necessary for product to dry.
  • bifenthrin + imidacloprid (Allectus GC SG Insecticide)-Restricted use. Highly toxic to bees and other pollinators exposed to direct treatment or residues on blooming crops or weeds. Do not apply or allow to drift to blooming crops or weeds if bees or other pollinating insects are foraging in the treatment area. Note: Neonicotinoid pesticides have been banned from use on public properties in some towns and counties (check with local authorities).
  • carbaryl (Sevin SL Carbaryl Insecticide)-Carbaryl is highly toxic to bees and other pollinators exposed to direct treatment or residues on blooming crops or weeds. Do not apply carbaryl or allow it to drift to blooming crops or weeds if bees or other pollinating insects are foraging in the treatment area.
  • chlorantraniliprole (Acelepryn Insecticide, Acelepryn G Insecticide)-For larvae at 0.1 to 0.2 ai lb/A. Max rate per treatment 0.25 lb ai/A and maximum 0.5 lb ai/A per year in broadcast applications in turf.
  • clothianidin (Arena 0.25G Insecticide, Arena 50 WDG Insecticide)-For adults or larvae. Do not apply while bees are foraging. Do not apply to plants that are flowering. Only apply after all flower petals have fallen off. Note: Neonicotinoid pesticides have been banned from use on public properties in some towns and counties (check with local authorities).
  • clothianidin + bifenthrin (Aloft GC G Insecticide, Aloft GC SC Insecticide, Aloft LC G Insecticide, Aloft LC SC Insecticide)-Restricted use. Not for use on golf course turf. Do not apply while bees are foraging. Do not apply to plants that are flowering. Only apply after all flower petals have fallen off. Note: Neonicotinoid pesticides have been banned from use on public properties in some towns and counties (check with local authorities).
  • cyantraniliprole (Ference)-Apply when adult billbugs first observed.
  • cyfluthrin (Tempo Ultra WP Insecticide, Tempo 20WP Golf Course Insecticide in WSP)-For adults.
  • deltamethrin (Deltagard G Insecticide, D-Fense SC Insecticide)-For adults. Not for use on golf course turf.
  • dinotefuran (Zylam)-Do not apply while bees are foraging. Do not apply to plants that are flowering. Only apply after all flower petals have fallen off. Note: Neonicotinoid pesticides have been banned from use on public properties in some towns and counties (check with local authorities).
  • esfenvalerate + prallethrin + piperonyl butoxide (Onslaught FastCap Spider and Scorpion Insecticide)-Not for use on golf course turf.
  • imidacloprid (Mallet 2F T&O Insecticide, several other trade names)-For larvae. Do not apply while bees are foraging. Do not apply to plants that are flowering. Only apply after all flower petals have fallen off. Note: Neonicotinoid pesticides have been banned from use on public properties in some towns and counties (check with local authorities).
  • gamma-cyhalothrin (Scion Insecticide)-Highly toxic to bees exposed to direct treatment or residues on blooming crops or weeds. Do not apply or allow to drift to blooming crops or weeds if bees are visiting the treatment area.
  • lambda-cyhalothrin (Scimitar)-Restricted use. For adults. 10 fl oz/A, 0.034 lb to 0.068 lb ai/A. Apply at 7-day intervals if treatment is necessary. Do not apply more than 0.36 lb of ai (52.4 fl oz of concentrate) per acre per year.
  • mint oil, geraniol + oil of rosemary (Furious Insecticide)-OMRI-listed for organic use.
  • permethrin
  • tetraniliprole (Tetrino)-For larvae at 16-32 oz/A, applied when adults are observed to control larvae for 3+ months. Maximum yearly rate is 64 oz/A.
  • thiamethoxam (Meridian 0.33G, Meridian 25WG)-Apply up to second instar larvae. Irrigate following application. Highly toxic to bees exposed to direct treatment or residues on blooming crops or weeds. Do not apply or allow to drift to blooming crops or weeds if bees are visiting the treatment area. Note: Neonicotinoid pesticides have been banned from use on public properties in some towns and counties (check with local authorities).
  • trichlorfon (Dylox 420 SL)-For larvae.