If irregularly shaped sections of your lawn are withering away, the problem could be grubs. These small beetle larvae live in the soil and feed on lawn roots.
To determine whether you have a grub problem, cut into your lawn near the edge of a brown area and lift the grass. If it comes up easily, as if you’re rolling up carpet, your yard has grubs. Odds are, you’ll see some of these milky-white, wormlike creatures with brown heads and three pairs of legs curled into a C shape (shown).
The remedy: Apply chemical insecticides with imidacloprid or halofenozide in July or August when grubs are immature. After a couple of days, reseed or replant any damaged areas. (Learn how to plant the perfect grass.)
To kill mature grubs this fall or next spring, combine Heterorhabditis nematodes—sold in pastelike form—with water and apply to the soil according to the package instructions.
Next week’s pest: There’s one other reason to target grubs—they’re a favorite food of moles, whose extensive tunneling can exacerbate the damage grubs do to your lawn. We’ll target ways to control the five species of mole common to the U.S. in an upcoming installment of Pest Patrol.
Essential information: Our updated Complete Lawn & Yard Guide offers how-to advice for planting and pruning and Ratings (available to subscribers) of a wide array of lawn and garden equipment. You’ll also find the best ways to deal with weeds, lawn diseases, and common insects as well as an interactive tour of major lawn problems.