Description

Adult: Grasshoppers are about 25-50 mm long with  robust bodies, hind legs with enlarged femurs for long distance jumping and relatively short antennae.
Egg: Eggs are about the size as a grain of rice, and are contained in pods of up to 100 eggs in the upper 2 inches of soil. 
Nymph: Five nymphal stages or instars occur. Instars grow from around 6 mm (1st instar) to 25 mm (5th instar). Wing pad size gradually increases with each instar until they can fly, indicating adulthood.

Life History

Female grasshoppers lay eggs in undisturbed soils in late summer and fall. Eggs hatch in mid to late spring when soil temperatures warm and new nymphs feed on nearby plants. In some years, populations can increase in undisturbed areas and move into crop sites where they cause massive defoliation. Most grasshopper species in Utah have one generation per year.

Damage

Grasshoppers have chewing mouthparts that leave random, ragged holes in leaves and flowers and can devour entire plants. They generally prefer young green plants of corn, lettuce, beans, carrots, onions, some annual flowers, and melons. Damage occurs in the early summer after rangeland weeds dry up and usually lasts a few weeks. 

Management

Because grasshoppers travel long distances, especially as adults, it is important to treat large areas. The best time to treat is in mid spring when nymphs are young.

Cultural

• Use floating row covers or lightweight plant fabric. Row covers will exclude the grasshoppers, and should be removed during crop flowering for pollination. This can be done in the morning hours when pollinators are most active.
• Hand removal. Grasshoppers can be handpicked and squashed, especially when populations are low.

Chemical

• Baits. The insecticide carbaryl is mixed with wheat bran to create a bait. Spread it evenly throughout the habitat and reapply weekly. The bait can also be placed inside a container, such as PVC pipe segments, to protect it from getting wet (wet bait is no longer attractive to grasshoppers).
• Dusts. Dusts have short residuals and must be reapplied weekly and after rain or irrigation.
• Sprays. Sometimes aerial sprays can be coordinated with the Utah Department of Agriculture and Food. The USDA threshold for rangelands is 9 nymphs per square yard; agricultural thresholds would likely be lower.

Biological

Nosema locustae is a biological insecticide bait that must be applied to early nymph stages and is specific to grasshoppers. After feeding on the bait, grasshoppers stop feeding, become lethargic, and die. The disease is contagious and will infect other grasshoppers that cannibalize diseased grasshoppers in the area.

More Information

• Grasshoppers
• Community-Wide Grasshopper Control