Sherwood Estates III

Grubs and How to Control Them

May 07, 2001

contributed by Oscar Rascon


Grubs.... These ugly critters have caused otherwise pleasant people to start personal crusades against this dumb, but hungry insect. It doesn't really make sense to get angry at grub, but it is a good idea to make sure they don't make a meal of your lawn.

Grubs feed on the roots of your grass. In areas of extreme damage the turf begins to brown and die, and the sod can be lifted up like a piece of carpet. To check for grubs, simply grab a handful of turf and tug. If grubs are there, chances are the sod will lift off. Grub damage can go unnoticed for weeks and even months on turf that is watered consistently. The grubs stay out of sight under the sod and, with enough water, the turf can appear healthy. While the damage may not appear quickly, it can completely devastate a lawn making major renovation the only solution.

There are many varieties of grubs (also know as white grubs). June beetles (and others) start the cycle by laying eggs in the thatch layer of your lawn. These eggs hatch out as baby grubs and begin eating their way through the thatch and into the soil. Grubs feed heavily through late summer and fall until cooler weather sends them deeper into the soil through winter. Come spring, they return to the surface to feed until they pupate (or go into a type of cocoon) which is when they change into the adult beetles and start the cycle again.

Grubs are not a concern until there are enough of them to form a damaging population. Healthy lawns can support a wide variety of insects without suffering noticeable damage. Grubs are not damaging until we find at least 8 to 10 per square foot. There are several different products on the market to control grubs as either a curative or a preventive treatment. What's important is making sure that the material is active in the soil where the grubs are present but before serious damage occurs. Apply to late (after extensive damage) and you'll get control of the grubs, but have a lawn repair job on your hands.