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Garden Help Desk: Getting rid of your grasshopper problem

March 19, 2018 GMT

Utah State University Extension provides informal education outreach to residents throughout the state. This question-and-answer column is designed to give you research-based information whether your gardening interest is producing fresh food, creating a landscape area or anything in between.

Question: My neighbor and I both had a lot of hungry grasshoppers in our yards last year. What can we do to get rid of them this year?

Answer: It won’t be possible to completely eradicate the grasshoppers, but there are some things you can do to keep their population low enough to prevent any serious damage to your yards and gardens.

Work together

You and your neighbor have already taken a first step to success by working together. Grasshoppers are very mobile, especially as they become more mature. You might manage to kill the ones you see in your yard, but there can be more in the surrounding area to take their place. The more neighbors you can recruit to your project and the wider the area of your control measures, the more successful you’ll be.

Control methods are most successful while grasshoppers are small nymphs. Once grasshoppers are larger and more mature, pesticides and biological controls are less effective. The grasshoppers that you’ll see this coming summer will come from eggs that were laid in August, September and October of last year. The eggs will hatch from late spring through mid-summer (probably May through early July). Since the youngest grasshoppers are also the most susceptible to pesticides, the time during and shortly after the egg hatch season is the most important time for control methods. The longer you wait, the less likely you are to be successful.

Female grasshoppers prefer to lay their eggs in undisturbed soils, so landscapes close to drainage ditches, fields, rural roadsides and abandoned, neglected or weedy lots are more likely to have grasshopper problems. If you live near an area like one of these, you’ll need to pay special attention to control practices at your perimeters. Talk to your neighbors with property like this, and encourage them to join your control program. You’ll also want to make sure you don’t let dry or weedy and neglected areas develop on your own property, where you have control over how the landscape is managed.

Pesticide sprays and baits are the most common control methods. There are many readily available products with active ingredients that are effective. Baits are usually grain-based products that include a pesticide. The bait should be spread evenly throughout the area where you expect grasshoppers to show up on your property.

Baits can be effective in open, dry, weedy areas where there isn’t as much plant life to serve as an alternate food source for grasshoppers. Pay special attention to the areas where your landscape borders those areas.

On smaller properties, like well-tended residential landscapes, sprays may be more effective than baits because grasshoppers can be attracted to the green landscape plants and ignore the bait. Well-tended landscapes are also irrigated regularly, and baits need to be refreshed after rain and irrigation, making them less convenient than spray products.

Keep in mind that pesticidal sprays that are effective for grasshoppers will also kill any other insects, including the beneficial insects that help to keep grasshopper populations under control. Apply these products only as needed and follow the label directions.

If you want to avoid conventional pesticides in your landscape, you might consider using a bait product that contains the protozoan Nosema locustae. This protozoan infects only grasshoppers and Mormon crickets. It isn’t quick-acting, but its effects can be long lasting as infected grasshoppers die and are eaten by other grasshoppers, who will also become infected. Apply this slow-acting bait product early in the egg-hatch season and refresh as needed to get the best results.

To recap:

• Recruit neighbors

• Take a careful look around your landscape

• Make a plan of action

• Be diligent this spring and summer

If you do this, you should see fewer grasshopper problems this coming summer and fall.