Keep Yard Pests in Check

R. L. Rhodes
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Keeping a green and healthy lawn means fostering a hospitable environment, but not everything that moves in will be equally welcome. We want grass and the organisms (like earthworms) that help maintain it, but the conditions for growing a strong lawn also happen to be conditions favorable to less helpful creatures. Too welcoming an attitude may even be counterproductive, as some bugs will, if left to their own devices, destroy the very plants you were after in the first place. The trick, then, is making your lawn inviting for the life you want to settle in, while making it inhospitable to the pests. Here are five common yard pests along with tips for keeping them at bay:

Ants

We tend to see ants as pests mostly when they’re riled enough to bite, but ants can also cause damage to your lawn. Their nests can disturb the roots of grass, and their workers can undermine your attempts to overseed by making off with the seeds themselves. If you’re having trouble maintaining the health of your grass and have noticed a number of large beds in your yard, ants may be part of the problem.

To curb ant populations, use an insecticide rated for ants. To expose more of the mound to the treatment, mow the lawn before application.

Cinch bugs

Cinch bugs are the vampires of lawncare, sucking the vital sap from the blades of grass while simultaneously injecting it with a toxin. This can result in yellowish patches in your lawn, and indication of morbidity that can ultimately kill the grass in those areas. The bugs themselves identifiable as tiny scale-like insects with needle-like mouths. Because they are most active in hot, dry weather, cinch bug damage is often mistaken for the effects of drought.

It’s important to catch cinch bugs early. The adults emerge in early spring, but damage may not be visible until after the first batch of eggs release hungry cinch nymphs into your yard. By the time temperatures reach the 70s, the females will be ready to lay their eggs in preparation for a second generation in the late summer. The speedy application of a pyrethroid insecticide, such as an Ortho product rated for outdoors, can help deplete invading cinch bug populations. Because they function poorly in adequate precipitation, regular waterings can also help curb cinch bug populations.

Cutworms & webworms

Cutworms and webworms are brown or gray caterpillars, often spotted or striped. They burrow in the soil and emerge by night to feed on the blades of your grass, but they can also lead to lawn damage by attracting birds that root in the soil for their lunch. Pyrethroid insecticides, like those used in Ortho products, are particularly effective against caterpillars.

Northern regions: Webworms tend to prefer cool-season grasses, like fescue or bluegrass, which are popular in Northern states. If your lawn consists of a cool-season grass, keep an extra close watch for webworms, particularly when establishing a new lawn. Shorter than cutworms, they can be identified by the silk lining they construct in their burrows.

Grubs

Several types of beetle produce the plump larvae known as white grubs, which can usually be found several inches below the surface of the soil. There they can feed on the roots of your grass for up to two or three years before maturing into full-grown beetles. Patches of dead grass that can be easily pulled up by the handful or in strips are a possible indication of a grub infestation.

Because they burrow more deeply during the winter months, it’s best to check for grubs after the soil temperature has warmed for spring. You can check for them by cutting away a small strip of lawn two to three inches deep. As the name implies, they are usually cream-colored or grayish, with darker sections at the end and posterior. When disturbed, they tend to curl defensively. Usually, a lawn can accommodate up to ten grubs per square foot without significant damage to the grass above. In numbers greater than that, you’ll almost certainly need to take steps to reduce their numbers.

Grubs will tend to be more active in warmer weather, so that’s the most effective time to treat. A cyhalothrin-based pesticide like Spectracide Thiaszicide disrupts the nervous system of grubs and other pests, and can by applied using a lawn spreader. For a more organic solution, try beneficial nematodes or a plant-based grub control like Monterey or Milky Spore. Thatch can inhibit the penetration of treatments to the depth needed to affect grubs, so consider dethatching your lawn before any applications.

Mole crickets

Another root-eater, mole crickets are identifiable by the powerful, shovel-like forearms they use for burrowing. In addition to making a meal of your grass roots, their digging can uproot seedlings. One tell-tale sign of the presence of mole crickets are the trailing mounds left on the surface of the soil by their tunnels, but you can test for their presence with a “soap flush”—a few tablespoons of detergent mixed into a gallon of water and poured over a three foot span of lawn. If your soil contains mole crickets, they should surface in response to the soap flush.

A conventional insecticide like Ortho Bug-B-Gon can be used to treat infestations. Beneficial nematodes are also an effective organic treatment for curbing mole crickets in your yard. They should be applied at dusk when the lawn is damp and receives little to no direct sunlight.

Grub image: bobistraveling/Flickr

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