Lawn Care: Prevent Grub Damage
by Kate McIntyre
Old House Web Columnist
Grubs are the white, worm-like larvae members of the scarab beetle family. They live underground and eat the roots of plants. Unfortunately, your lawn is one of their favorite meals. Patches of lawn that have turned brown might be signs of a grub invasion. If you can easily pull up the dead turf, you've probably got grubs.
Although you are more likely to see the damage grubs do in the spring, they most voracious in the fall. In addition to damaging your lawn themselves, they often attract predators such as skunks and moles, which will dig holes in your perfect sod as they look for dinner. Here's how to assess your lawn's grub risks and how to minimize the damage.
Counting Your Grubs Before They Hatch
To figure out if grubs are a problem in your lawn, you should do a quick estimate of their density in the late summer. Take samples from several areas around your yard using a bulb planter. Dump the cores of dirt you remove with the bulb planter out onto a flat surface and count any grubs you see. You can estimate that the bulb planter gathers approximately one-tenth of a square foot of lawn, so you can figure out the total number of grubs in a square foot by multiplying your count by ten. If you are consistently finding over ten grubs per square foot of lawn, you should consider your treatment options.
Getting Rid of Your Lawn's Grub Problem
To combat the grubs in your lawn, you can choose to employ an all-natural method or a chemical one. Raccoons and skunks are not the only natural predators of grubs. Microscopic worms called nematodes also can help to reduce your grub population. You can purchase live nematodes from garden supply stores and spread them around your yard with a pump sprayer. The nematodes will attack the grubs, reducing their population. Nematodes are a good option if your lawn is already well established and you have children or pets. If your lawn is still new and tender, you might want to consider a chemical insecticide. To minimize its environmental impact, you can target the specific problem areas you found when estimating the density of grubs in your lawn.
Grubs might seem like a tough problem for lawns, but you have good options for controlling their population. With a little detective work, you will soon know which areas of your lawn are particularly at risk, and you will be ready to start your treatment plan.
About the Author
Kate McIntyre is a writer in Portland, Oregon. She holds a BA from Harvard University and an MFA in fiction writing from Oregon State University.