They live in the soil for one to three years depending on the species and feed on plant roots, thatch, and decaying organic matter. In most cases, grubs should be controlled if more than seven grubs per square foot are found in a sample of sod. Treat with an insecticide when the grubs are small and feeding near the surface in late August and September. It is a long-term management strategy that requires two to three years to become established.
Insecticides are available, but timing of application for different species is critical.
It is also difficult to move the insecticides through a thatch layer to the root zone where the white grubs reside. If you have a grub problem, have them properly identified by submitting samples to your local county Clemson Extension Service office.