Master Gardeners: Dealing with Grubs in Your Lawn

This is Steve Rulison bringing you information on Shore friendly living and gardening from the Master Gardeners and Virginia Cooperative Extension. From my perch near the mouth of Occohannock Creek, I recorded virtually no rain last week.

Have you ever found a grub while digging in your lawn? It could be a Japanese beetle or European chafer. Evidence of an infestation of white grubs appears as grass begins to turn brown due to root damage. Usually the turf can be rolled back like a rug to reveal grubs. Mole or skunk damage also indicates the presence of grubs.

The European chafer adult is a small golden tan to light brown beetle, oval in shape, and about 1/2″ long. The grub is about 3/4″ long, grayish white with a brown head and six legs. The European Chafer grubs are distinguished from other white grubs by the parallel rows of spines on their raster. The raster is on the last segment of the grub and is formed of hairs.

The adult Japanese beetle is about 1/2″ long with a shiny, metallic-green head and body. The grubs are usually small with light brown heads. The rastral pattern on the grubs forms a V. 

European chafers lay their eggs in late June; Japanese beetles in July and August. The eggs hatch and the young grubs begin feeding on grass roots within one to two weeks. Dry soils in July and August cause many eggs to die from moisture stress. Grubs feed until fall and then burrow deep into the ground to overwinter.

In spring, the grubs burrow upwards to grass roots, resume feeding until late May, and then transform into pupae. Adult Japanese beetles emerge around the first week of July; European chafers about two weeks earlier.

Options for control include good cultural practices, that is keeping grass at 2 inches or higher, monitoring, and chemical control. Chemical controls and the timing of application vary with the different species of grub. As a general rule, apply preventive controls from April to mid-July and curative controls from late July through August.

For answers to Gardening questions and more, call your local Accomack or Northampton County Extension Office. Here on the Shore call either 678-7946 or 787-1361.

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