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USU entomologist highlights tips to control grasshoppers

USU Extension writer

There are two basic keys to success in combating grasshopper infestations in the yard and garden.

The first involves working as a neighborhood to treat as broad of an area as possible as soon as grasshoppers begin to move into yards from nearby open fields and rangelands.

The second key centers around initiating control while grasshoppers are young, explained Diane Alston, Utah State University Extension entomologist.

When grasshoppers become adults, the insects eat much more per day and can fly over treated areas.

Grasshoppers lay eggs in undisturbed soil in the late summer and fall.

Eggs hatch the following spring and the nymphs - young grasshoppers - walk until they find attractive vegetation to feed on.

Grasses and forbs growing on open lands can satisfy their hunger early in the season, pointed out Alston.

But as populations increase in size and non-irrigated plants dry with warming temperatures and reduced rainfall, the grasshoppers will move to where the insects can find lush, green plants to eat.

This is when the grasshoppers become a pest in the landscape and garden.

The USU Extension entomologist suggested that Carbon County residents consider several tips for control.

The insect recommendations include:

•Mechanical and chemical methods can be used to control grasshoppers.

Mowing a wide swath around borders of open fields can reduce migration of grasshopper nymphs walking across the mowed boundary.

Insecticides should also be applied to boundaries between home yards and open fields, hedgerows, roadsides, drainage ditches and other weedy and unmanaged lands, continued the USU Extension entomologist.

In order to be effective, mowing and insecticide treatments should be initiated while grasshopper nymphs are small and before their developing wing pads are noticeable.

•There are three types of insecticide formulations that can be used for killing grasshoppers: baits, dusts and sprays.

Baits consist of wheat bran combined with the insecticide, carbaryl, or a natural grasshopper pathogen, Nosema locustae.

Baits should be spread evenly throughout the boundary habitat and grasshoppers will consume the bait as they forage.

Baits selectively kill only grasshoppers and other foraging insects.

The baits must be reapplied following rainfall or sprinkler irrigation.

Examples of carbaryl bait brands include Lily Miller Grasshopper Bait, Sevin 5 Bait and Eco Bran 2 percent, according to Alton.

Baits containing the natural pathogen include NOLO Bait Biological and Planet Natural Semaspore Bait.

•Carbaryl is the only type of dust registered for home yard application, advised the USU Extension entomologist.

Dusts are easy to apply, but are more expensive than sprays and must be reapplied after rain or irrigation.

A number of insecticide sprays that can suppress grasshoppers include malathion, permethrin (Spectracide, Bonide Eight, Basic Solutions), bifenthrin (Allectus, Brigade, Sniper and Talstar) and carbaryl (Sevin).

Some spray products are not for use on edible plants and some are restricted to licensed applicators only, so local residents should be sure to read the product label before purchase and application, cautioned Alton.

Sprayable formulations tend to be less expensive and can kill on contact and when grasshoppers eat the treated vegetation.

Sprays are not selective and can kill beneficial insects, pollinators and susceptible animals.

Therefore, local residents should remember that careful application and appropriate timing are important to protect non-target animals, warned the USU Extension entomologist.

•USDA APHIS offers assistance for grasshopper control on public lands.

When grasshoppers occur in high densities, landowners may work together to receive state and federal aid to plan and conduct a cooperative management program, indicated the USU Extension entomologist.

Carbon County residents should contact local USU Extension or Utah Department of Agriculture and Food offices for assistance with grasshopper management, concluded Alton.

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