Lawn Pests

Did you enjoy our mild winter? Well, the insects did too. It didn’t get quite cold enough this year to kill off most of the insect population, so you can expect to have a battle on your hands this summer. This month, I’m going to talk about two of the most common pests that attack your lawn: the white grub, and the cinch bug.

If you have a lawn, you probably have grubs. These are those gross looking, white, squishy, C-shaped things you find in your soil. Grubs are the larvae of several different kinds of beetles. These beetles lay their eggs in your lawn in June and July, and the newly hatched grubs spend the summer, fall and winter in your lawn, chomping on the roots of your grass. By spring, they are fat and happy, and ready to hatch into a new generation of adult beetles.

Your lawn isn’t the only food grubs enjoy. They’ll munch down on the roots of any plant, including vegetables, annuals, and perennials. They also enjoy a meal of decaying thatch one in a while. But lawns seem to suffer the most damage from these ravenous white worms. A grub-infested lawn needs frequent light waterings, since the roots of the plants are damaged and can’t absorb water so efficiently. The damage is worst in the fall, since the lawn is in a semi-dormant state.

Where you have grubs in your lawn, you’ll notice that the turf feels rather spongy, brown spots develop, and you can pull up patches of grass easily, usually to reveal the culprit. Often the lawn looks bluish all over. By the way, don’t worry about treating for grubs unless you have more than 12 to 15 of those yucky creatures in a one square foot area. Most healthy lawns can handle a few of them without a problem.

Birds, especially starlings and robins, love to eat both the beetles and the grubs, so attracting birds to your outdoor living area will decrease the number of grubs in your lawn. If you can find them, Margosan®, Neem®, or Scanmask® are good organic controls, and the GardensAlive® catalog sells nematodes that are moderately effective on our grub population. Nematodes should be applied at the end of July or the first week of August, since you want to get the newly hatched baby grubs. Nematodes aren’t as effective on the larger ones.

Usually though, you have to resort to using Diazinon®, Dursban®, or Oftinol®, all potent insecticides. Unfortunately, these chemicals also kill all the beneficial insects too, including those valuable earthworms, and are toxic to fish, birds, pets, and even you, if you don’t apply them properly.

The other scourge of your lawn is the chinch bug, a tiny little black bug about 1/5 of an inch long, which stinks when it’s crushed. Chinch bugs and their larvae congregate down in the base of your lawn, hiding out in the thatch, and the top level of your soil. They spend winter down their, too, and start to emerge as adults in March.

Although the adult sucks plant juices from your lawn, it’s the little red nymphs that do most of the damage. They feed on the stems and leaves of the grass injecting a poison into the leaves. Your grass will turn yellow and dies off in patches. So, if you notice circular yellow patches in your lawn, which look worse in the center, suspect chinch bugs. To confirm your diagnosis, spread the grass apart with your hands, and look for small red and black bugs. If you’re still not sure, remove both ends from a large can, and push one end down into your lawn. Fill the can with water from your hose. Come back in 10 or 15 minutes, and see if dead chinch bugs are floating on top of the water.

Chinch bugs like hot, dry, sunny lawns, so regular watering will reduce if not completely eliminate the chinch bug population. A heavy infestation can be controlled by spraying your lawn with insecticidal soap every 2 or 3 days for a week or two. Pyrethrum or sabadilla dust are also effective, as is Neem®. If you decide to go the inorganic route, Dursban® is the pesticide of choice.

Whatever method you choose to fight back against these lawn menaces, be sure to read, and follow, the label directions. You want to eliminate the bugs, not the wildlife.

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