White grubs are soil-dwelling larvae of certain beetles. They feed on the roots of turfgrass and other plants, destroying the plants ability to absorb and transport water and nutrients. White grubs are pudgy, off-white larvae with a brown head and typically are bent in the shape of the letter "C." Full-grown length varies from 3/4 to 1 inch. The white grubs that routinely damage lawns are called annual white grubs because they have one generation per year and take one year to complete their life cycle of egg, larva, pupa, and adult.
The adult beetles of our annual white grubs are either Japanese beetles or masked chafers. They emerge and begin flying in late June and lay eggs in the turf during July. The eggs hatch in 2 to 3 weeks and tiny white grub larvae begin to eat the grass roots. The grubs grow rapidly and are fully grown at by late August or September. Feeding by the grubs prunes the roots from the plants and causes the grass to wilt and fade. Extreme feeding by populations of 10 or more annual white grubs per square foot will cause the grass to die. White grubs move several inches deep in the soil to spend the winter. The move back near the surface in the spring time but cause little additional damage as they wait to pupate in June, emerge as adults and start the cycle over.
The timing of the grub control application is the most important part of the job. Grub elimination must be timed to target the youngest stage of the grubs that are feeding close to the surface. We apply our Systemic granular application to turf from early June through late July to have the best control.