Turfgrass-White grub

Includes Aphodius spp.

Pest description and crop damage White grubs are the larvae of a number of scarab beetle species. The most common in the PNW are A. granaris, a European species, and A. pardalis, a west coast species. Other white grubs found in the PNW are larvae of May or June beetles, (Polyphaga spp. and Phyllophaga spp.). Adult aphodius are small (2.2 mm by 4.9 mm), shiny black, with dull red or yellow markings. They feed on all kinds of debris including dung, leaf litter and carrion. Larvae sizes vary; they have robust, cream-color bodies and black heads. White grubs feed primarily on roots. Turf damage generally appears as patches of dead turf that are not anchored to the soil. Symptoms may occur from spring through fall. In general this is not a consistent pest of turf in the PNW. Most documented damage has occurred on golf courses.

Biology and life cycle Adult aphodius are found first in May through June, and again in August and September. The first larval population causes the most damage and peaks in June-July. These insects may have two generations per year.

Scouting and thresholds Damage tends to be visible in early to mid-spring as patches of dead or dying turf. Damage first becomes noticeable when larval densities reach 100/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

Spray when grubs are active near the soil surface. Irrigate the treated area immediately after application with 0.5 to 1 inch water to wash insecticide into underlying soil. 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.

  • Beauvaria bassiana-Some formulations are OMRI-listed for organic use.
  • bifenthrin
  • carbaryl
  • chlorantraniliprole
  • clothianidin
  • imidacloprid

Management-chemical control: COMMERCIAL USE

Spray when grubs are active near the soil surface. Irrigate the treated area immediately after application with 0.5 to 1 inch water to wash insecticide into underlying soil. 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.

  • acephate (Orthene Turf Tree & Orn. WSP)
  • azadiractin (Nemix 4.5 IGR/ org. prod., zaMax AG 0.6)-OMRI-listed for organic use.
  • bifenthrin (Talstar, Capture, Brigade)
  • carbaryl (Sevin Brand RP4 Carbaryl, Lebanon Sevin 7G Granular Insect Control, Sevin SL Carbaryl Insecticide)-For larvae.
  • chlorantraniliprole (Acelepryn Insecticide, Acelepryn G Insecticide)-For larvae.
  • chlorpyrifos (Andersons Golf Products Insecticide III, Dursban Pro Dursban 50W In WSP Speciality Insecticide, Hatchet Insecticide, Nufos 4E Insecticide, Vulcan, Quali-Pro Chlorpyrifos 4E Insecticide, Warhawk, Warhawk Clearform)-Retail sale of products containing chlorpyrifos for residential use ended 12/31/01.
  • clothianidin (Arena 0.25G Insecticide, Arena, 50 WG Insecticide, Arena 50 WDG Insecticide)-Apply as soon as overwintering adults are seen in the spring. Note: Neonicotinoid pesticides have been banned from use on public properties in some towns and counties (check with local authorities).
  • dinotefuran (Zylam)-Provides only suppression of white grub larvae. Must apply prior or during egg hatch for control. Note: Neonicotinoid pesticides have been banned from use on public properties in some towns and counties (check with local authorities).
  • imidacloprid (Fortify Season Long Grub Control, Adonis 2F Insect Conc., AmTide Imidacloprid, Avatar PLX Insecticide, Lesco Bandit 0.5G Granular Insecticide, Lesco Bandit 2F Insecticide, Lesco Bandit 75 WSP Insecticide, Malice 0.5G, Malice 2F Insecticide, Malice 75WSP, Mallet 0.5G Insecticide, Mallet 2F Insecticide, Mallet 2F T&O Insecticide Mallet 75 WSP Insecticide, Mallet 7.1% PF Insecticide, Merit 0.5G Insecticide, Merit 2F Insecticide, Merit 75WP Insecticide, Merti 75WSP Insecticide, Midash 2SC T&O, Prokoz Zenith 0.5G Insecticide, Prokoz Zenith 2F Insecticide, Quali-Pro Imidacloprid 0.5G, Quali-Pro Imidacloprid2F T&O, Quali-Pro Imidacloprid 75 WSB Insecticide in WSP)-For larvae. Note: Neonicotinoid pesticides have been banned from use on public properties in some towns and counties (check with local authorities).
  • spinosad A & D (Conserve SC Turf & Ornamental Insect Control)
  • thiamethoxam (Meridian 0.33G Insecticide, Meridian 25WG Insecticide, Flagship 25WG Insecticide)-Note: Neonicotinoid pesticides have been banned from use on public properties in some towns and counties (check with local authorities).
  • trichlorfon (Dylox 6.2 Granular, Dylox 420 SL Turf & Ornamental)-For larvae.