The white grub, larval stage of the Curculionidae family of beetles, reside below the grass thatch and create dead spots in turf.

White grubs are the larva of weevils, a Curculionidae family beetle that commonly attack the roots of turfgrasses and/or ornamental plants. White grubs grow up to become June beetle varieties, various chafer types, Japanese Beetles, Asiatic garden beetles, Oriental beetles, black turfgrass ataenius, et al.

Examine Your Turf

White grubs are found near the soil surface and are identified by their three pairs of legs found close to the head of their 1-2 inch curled bodies. Grubs feed on grass, grass roots (can cause dead patches) and roots of flowers.

June beetles, for instance, have a three year life-cycle. In June, the adult lays eggs in the soil and white grubs emerge within two weeks and feed during the warm months before overwintering deeper in the soil. Early the following summer, the grubs move close to the soil surface and begin feeding again. This second year is when they do the most damage. After a short feeding period during the third summer, the white grub pupates into adulthood, overwinters in the soil and lays eggs the following summer, thus completing its life cycle.³

Science Steps In

In May 2005, Bayer Environmental Science (BES) received registration from the EPA for Allectus SC, a granular or liquid formulation to control of turf pests above and below the surface.4 Of course, the degree to which you have to deal with grubs and surface insects depends on your local soil. In the North the primary pest concern is grubs, with fluctuating surface insect problems. The opposite is true in the South.

The SC formulation is labeled for both soil and foliar applications. For residential size properties, the product has 0.81 pounds of active ingredient per gallon; for large turf areas, the ratio is 0.63 pounds of active ingredient per gallon, but as always, refer to label for applications rates. The label says one application can provide up to 12 weeks of residual control.

Grub damage on a soccer field. White grubs feed on grass and grass roots. Some insecticides (e.g., Merit .5G Systemic Insecticide Granules) contain an active ingredient that can give season long control of white grubs in a single application. It should be applied no sooner than mid-July and no later than early August, but check with your extension office to see if this schedule is different in your area. ?EUR??,,????'??Systemic?EUR??,,????'?? indicates that plant roots uptake the product. As pests feed on the plant, they ingest the insecticide.

A Healthy Lawn

A healthy lawn is the best protection against white grubs. A well-watered, fertilized, aerated lawn will provide resistance against white grub attack. Good root growth is helpful as the adults prefer to lay their eggs in thin grass. If the lawn is not established or if it is being reseeded, choose a resistant grass variety, such as an endophytic grass which contains a fungus that repels white grubs. Planting geraniums in your garden will also repel white grubs.

3:Inches. In extensively damaged areas, the sod, with its roots cut off, can be easily pulled back by hand. Grubs are typically located near the top three inches of the soil. Source: savvygardener.com