The Grasshopper—Know Your Landscape's Enemy
There are 548 species of North American grasshoppers, with about 400 of these located on rangeland in the 17 western states. About two dozen of these are considered potential agricultural pests.
And you'll likely find some in your lawn and probably in your gardens, depending on where you live.
Grasshoppers are a food source for groups of parasites and predators—insects, spiders, and other animals collectively referred to as "natural enemies."
These animal groups maintain a constant pressure throughout their range.
Natural enemies significantly affect populations, are a key to avoiding grasshopper outbreaks, and are the first line of defense during outbreak events.
Some species may be considered beneficial because of their preference for weeds, or because they're a food sources for wildlife. Others are either harmless or cause only minor damage to plants.
Controlling Grasshoppers
There are several different methods that nature has provided for the control of these pests. Some of these controls are:
Birds
Many bird species eat bugs, making bird populations ideal for helping to limit grasshoppers, along with other control methods.
Some of the larger species, such as kestrels (sparrow hawks), gulls and meadowlarks, can capture in excess of 100 per day.
Grasshoppers are a highly preferred food for the young of many kinds of songbirds, upland shore birds, game birds (quail, grouse, pheasants, and turkeys), and even certain hawks and owls.
These pests are especially important for successfully raising young by many bird species.
Many wildlife species, like this lark bunting, choose these critters as food for their young.
Wild Turkeys love these pests too.
Egg Parasites
Grasshopper eggs are normally deposited in clusters, called egg-pods, placed just below the surface of the soil.
The eggs are attacked by wasps of the Scelionidae family. Members of this wasp family are the only true parasites of the eggs.
Egg Predators
In North America, the larvae of blister beetles (meloids) are an important group of predators of grasshopper eggs. However, in Australia, Africa, and other parts of the world, blister beetles are of little or no importance.
Below is an egg pod with loose eggs.
Nosema locustae
This disease-causing microorganism has been investigated as a potential biological control agent of grasshoppers for many years. It was selected in the early 1960s for development as a microbial control agent for use in long-term suppression of this pest.
Nosema locustae is the only registered microbial agent that is commercially available for control of this rangeland pest.
Nosema has been studied more than any other microbial control agent for the suppression of grasshopper populations. Applications of Nosema formulated on a wheat bran bait have resulted in numerous successful introductions of the pathogen into field populations.
Grasshopper Photos and Territories
The alpine feeds on both forbs and grasses, and will eat fungi and injured or dead arthropods.
The bigheaded is a serious pest of grasses. It is often the dominant species in outbreaks on rangeland.
The bluelegged is a heavy feeder on native grasses, particularly western wheatgrass, which abounds in its preferred habitats.
The brownspotted feeds on grasses and sedges. When adults are abundant in spring, they cause some of the first grasshopper damage to rangeland.
The differential is a severe pest of crops including small grains, corn, alfalfa, soybeans, cotton, various vegetables, and deciduous fruit trees.
Mormon crickets damage forage plants on rangeland and cultivated crops in the path of their migrations.
Northern feed principally on forbs but they may also feed at times on certain grasses.
The Carolina is a minor pest of rangeland grasses. Populations occur chiefly in disturbed areas where it feeds mainly on several species of weeds.
The fourspotted lives in assemblages of grasshoppers inhabiting mixedgrass, shortgrass, and desert prairies of the West.
It's usually a subdominant member of the assemblages, but it occasionally becomes the dominant species.
The Kiowa feeds on high-quality forage grasses and sedges.
It often becomes an injurious component of outbreak populations in the mixedgrass prairie.
This little spurthroated is an economically important species, becoming abundant in grasslands and feeding on both grasses and forbs.
In a rangeland assemblage, it's sometimes the dominant pest.
The migratory, a mixed feeder of grasses and forbs, is a serious pest of both crops and grasslands.
It causes more crop damage than any other species in the United States.
The obscure concentrates its feeding on blue grama, an important forage grass for livestock on western grasslands.
It ingests the green leaves and occasionally cuts and drops them.
Because of its usual low densities on rangeland and its preference for poor forage plants, such as the scurfpeas, the Packard in its natural habitat causes little damage.
The redlegged is a crop pest. During outbreaks of the species, it may severely damage alfalfa, clover, soybeans, and small grains.
The spottedwinged grasshopper is a pest of rangeland grasses, especially in areas of the mixedgrass prairie where the texture of soils is sandy loam.
There it's often the dominant species.
The striped grasshopper is a pest of grasses and sedges.
It climbs the host plant and with head up chews on the green leaves.
Because of its low densities in most western grasslands, the threebanded does not appear to be of great economic importance either as a damaging pest or as a beneficial insect.
Because it feeds almost exclusively on grasses and sedges, the velvetstriped grasshopper is a potentially damaging pest of rangeland.
Because the whitecrossed grasshopper feeds on valuable forage grasses and increases to high densities in certain habitats of the mixedgrass prairie, it's occasionally an important pest species.
The whitewhiskered grasshopper is a pest of rangeland grasses.
All grasshopper range photos courtesy of the USDA.
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