How to Stop Grasshoppers From Eating All of Your Plants

Gardeners and grasshoppers are rarely on friendly terms. A grasshopper outbreak (when swarms of insects hatch and begin feeding at the same time) can devastate a small garden in a few hours. Huge appetites combined with the ability to easily jump or fly from plant to plant make grasshoppers one of the most destructive garden pests. They are also one of the toughest insects to control because they move so quickly, thanks to their big back legs and active wings. Not only do they readily move between garden patches in one landscape, but they can cover great distances as they move from one neighborhood to another. Combat a grasshopper outbreak with these tips.

Grasshoppers are common throughout the U.S. You might see them in shades of green, gold, or brown. They chew ragged-looking holes in plant leaves. In some areas, they begin feeding in early summer and continuing eating green foliage until the first hard frost in fall, becoming more numerous as the season wears on. There are more than 100 types of grasshoppers and they eat all kinds of different plants. Some species eat weed plants and grasses of little garden value, while other species feast on vegetable crops such as lettuce, carrots, beans, and corn and prized perennials.

Many grasshoppers emerge in spring from eggs laid the previous fall. A cool, wet spring will destroy many of the newly hatched grasshoppers. A dry spring also presents challenges because there's often not enough plant growth for the hatchlings to eat. Weather conditions in spring at the time of hatch have a significant impact on how many of the insects survive to invade your garden.

Having grasshoppers invade your garden doesn't mean all your plants are goners. Here's how to control their numbers, and prevent grasshoppers from taking over.

Plant flowers, such as marigolds, calendula, sunflower, aster, alyssum, or dill nearby to attract beneficial insects such as robber flies. A few other garden predators, such as spiders and toads, will also help keep grasshoppers under control.

Many birds, such as kestrels and larks, eat large quantities of grasshoppers. Provide a water source and nesting habitat to encourage birds to take up residence in your yard. A diverse selection of native trees and shrubs will help attract birds.

A grasshopper disease called Nosema locustae can slowly kill the pests. It's available as a dry, flaky product under the label Nolo Bait, which you can apply to areas where grasshoppers lay their eggs. It’s important to reapply it after a rain. It's most effective on young grasshoppers, but not all grasshopper species are susceptible to the disease. Another option is a garlic-based repellent ($12, Arbico Organics).

If you choose to use insecticides, there are a couple of important points to know. First, insecticides don't offer complete control because grasshoppers travel so much that the products you use may not kill the insects until after they've done their damage in your garden and gone to someone else's. Also, insecticides also won't keep new grasshoppers from coming into your garden. And the products that will kill grasshoppers also kill beneficial insects at the same time, so use them with extreme caution. Look for products containing carbaryl or permethrin such as Sevin Insect Killer ($14, The Home Depot). Apply insecticides when eggs begin to hatch in May or June to control grasshoppers when they are young and less mobile.