Springtime, while grasshoppers are still nymphs, is the best time for communities or neighborhoods to work together to suppress grasshopper populations. Treating as wide an area as possible is the key to success. When grasshoppers become adults, they can travel great distances and may not remain in one area long enough for an insecticide to be effective.
How to Identify Nymphs
Grasshoppers go through five nymph stages before becoming adults. Look closely at a few individuals to assess the size of their wing pads (see diagram below and table at right). Grasshoppers that are able to fly have already reached the adult stage. Mobility increases after the 4th instar, so insecticide treatments are not as effective on 5th instar or adult stages.
General Sizes of Grasshopper Stages
1st instar
1/4 inch
2nd instar
3/8 inch
3rd instar
1/2 inch
4th instar
3/4 inch
5th instar
1 inch
Adult
1.5 inches
Where To Treat
Open Fields
Hedgerows
Boundaries between yard and open space
Roadsides
Drainage ditches
Other weedy areas
Treatment Options
Bait + Insecticide:
wheat bran + carbaryl or Nosema locustae (a natural grasshopper pathogen) that must be consumed
spread evenly through the habitat, grasshoppers eat the bait as they are foraging for food
easy to apply, but expensive
selectively kills only grasshoppers and other foraging insects
must be reapplied frequently and immediately following wetting events (rain, sprinkler irrigation)
very effective option
Dust (carbaryl):
easy to apply, but expensive
does not readily adhere to foliage and must be reapplied frequently
*Biological insecticide that contains Nosema locustae must be applied at early nymph stages 1not for edible plants 2restricted use
For More Help
Some county weed offices will provide sprayers to use for free, but the applicator must purchase the insecticide.
USDA-APHIS is responsible for control programs against grasshoppers on public lands. When grasshoppers occur at high numbers, owners may join together to receive state and federal aid in planning and conducting a Cooperative Rangeland Grasshopper Management Program.
Damaging Species in Utah
Redlegged grasshopper (Melanoplus femurrubrum)
Adults are 1-1½-inch long. This is the most widely distributed species, and prefers tall forbs, grasslands, meadows, crop borders, rangeland, and roadsides.
Adults are 1¾-inch long and live in fields, open woods and along the edges of water, and feed on grasses, weeds, and crops.
Twostriped grasshopper (Melanoplus bivittatus)
Adults are 1¼- 2-inch long, and prefer tall, lush, herbaceous, vegetation, and reside in ditch banks, roadsides, and crop borders. This species can be a major pest in small grains, alfalfa, and corn. It is one of the first species to appear each season.
Migratory grasshopper (Melanoplus sanguinipes)
Adults are 1-inch long and prefer forbs, grasslands, and meadows. This grasshopper causes more crop damage than any other species of grasshopper on small grains, alfalfa, clover, vegetables, and ornamentals.
Asparagus beetle and spotted asparagus beetle are leaf beetles in the family Chrysomelidae. These beetles feed exclusively on asparagus and are native to Europe. Asparagus beetle is the more economically injurious of the two species.
Sap beetles are typically considered a secondary pest of corn and overripe fruits and vegetables. Sap beetles are broadly identified by their small and ovular bodies and club-shaped antennae. Adult beetles feed on corn silk, pollen, and tassels. Larvae fe
n Utah high tunnel production, there are a variety of caterpillar pests (larvae of moth and butterfly species) that cause economic damage to crops. Common caterpillar pest species found in Utah include hornworms, tomato fruit worms, imported cabbage worms
Thrips are a common pest that can be found on many high tunnel crops, plus hundreds of weed species. Two species commonly found in Utah include Western flower thrips and Onion thrips. Bean thrips may also occur in the state.
In Utah, there are three main caterpillar pests of cabbage and mustard family plants: imported cabbageworm, cabbage looper, and diamondback moth. The injury they cause is similar.
Corn earworm (CEW) is the most destructive insect pest of sweet corn in Utah. CEW will also attack field corn, and pepper, and tomato fruits. The adult is a tan-brown moth that is most active at dusk; moths can be carried on wind currents and may travel u
Western corn rootworm is one of the most devastating corn insect pests in the United States. In some years, corn rootworms can cause up to $1 billion in yield loss and control costs.
Banks grass mites (BGM) and two-spotted spider mites (TSSM) are important agricultural pests of corn and a wide variety of other crops, garden, and landscape plants.
Banks grass mites (BGM) and two-spotted spider mites (TSSM) are important agricultural pests of corn and a wide variety of other crops, garden, and landscape plants.
The European earwig is an omnivore; it feeds on detritus, fungi, plants, and insects. Earwigs can injure the buds, leaves, flowers, and fruits of a broad range of plants, including fruits, vegetables, and ornamentals; they can be a nuisance pest by enteri
Pest managers cannot afford to take a pest management action without knowing if it is economically sound. Treating a pest needlessly is not conducive to making a profit. Other values such as aesthetics of the management situation (pertinent to landscapes
Flea beetles are common and problematic in Utah. They are present in late spring and early summer on many vegetable crops and ornamental plants. Adult flea beetles are small, shiny insects that have enlarged hind legs, allowing them to jump great distance
Grasshoppers are among the most conspicuous insects in Utah and are viewed by many as also among the most injurious to our crops and rangelands. We must also understand that because outbreaks can occur simultaneously across the landscape, suppression prog
“Leafminer” commonly describes the larval stage of various insects, but those that feed on vegetable crops are most commonly small yellow-and-black flies in the order Diptera. Vegetable host plants include leafy greens, beet, pea, tomato, onion, squash, a
Onion thrips are the most injurious insect pest to onions in Utah. Immature and adult thrips prefer to feed on young leaves in the inner neck of plants. Moderate to severe thrips feeding causes reduced bulb size.
Western flower thrips are native to western North America and are widespread throughout this region. This species feeds on hundreds of different weed and crop hosts.
Slugs and snails are rated by many gardeners as the worst garden pests. Considering their competition, this is a dubious honor. These pests are not insects but are mollusks that are more closely related to shellfish, such as mussels and clams.
Mites are small arthropods that are more closely related to spiders and ticks than to insects. Mites in this group are web spinners, hence the name “spider” mites. They are an important and destructive group of pests to agricultural crops worldwide.
Entire plants may wilt when squash bug-feeding severs xylem vessels in vines. Injection of a toxin during feeding has been proposed as a cause for rapid plant wilt, but no salivary toxins have been confirmed in squash bugs.
Aphids are a diverse family of insects with many species that inflict similar plant damage and can be managed using similar tactics. This fact sheet will focus on four of the most common aphids that are pests of vegetable crops in Utah.
Wireworms are the immature form (larvae) of click beetles. Severe damage from wireworms in Utah is rare. Wireworms live in the soil and feed on seeds, roots, crowns, and stalks of various plants.