With about 600 different species inhabiting areas of the United States, grasshoppers are common across the country. About 30 of these species are considered to be garden pests and detrimental to plants, but some grasshoppers can also be beneficial insects.
Benefitting the environment, grasshopper excrement provides nutrients to fertilize plants. The grasshoppers themselves are also food for birds, lizards, spiders, and other arthropods and insects.
Damage from Grasshoppers
However, grasshoppers are herbivores, feeding on grasses and the leaves and stems of plants, so when large numbers of certain grasshopper species infest farms or garden areas, they can cause extensive crop damage and loss. In peak years, grasshopper infestations can destroy or consume entire crop fields.
Although grasshoppers will feed on a vast array of plants, a preference is often shown for – and the greatest destruction often caused to -- small grains, corn, alfalfa, soybeans, cotton, rice, clover, grasses, and tobacco. They may also eat lettuce, carrots, beans, sweet corn, and onions. Grasshoppers are less likely to feed on plants such as squash, peas, and tomatoes leaves. The more numerous the population of grasshoppers, however, the more likely they are to feed on a variety of plants outside those of greatest preference.
Grasshoppers are most likely to cause damage in sub-humid, semi-arid areas in the middle of the U.S. – from Montana and Minnesota to New Mexico and Texas.
- are reddish brown to olive green, depending on species.
- may be as long as 1-3/4 inches, with narrow bodies.
- have distinctively long, angled back legs, enabling them to be strong jumpers.
- have protruding heads dominated by large eyes and chewing mouthparts.
- have wings and can fly.
Young grasshoppers are smaller than adults and are wingless. When first hatched, these nymphs will be white. As they grow, they will take on the color of the adults of their species, and wings begin to appear as small pads.
Grasshoppers will start being seen in early spring, with the greatest numbers generally occurring in mid-summer. In addition, grasshoppers populations are likely to be highest when the weather is hot and dry.
Natural and Organic Control of Grasshoppers
Because grasshoppers are very mobile, they are also very difficult to control. The best way to control grasshopper damage is to prevent the growth of populations:
- Till the ground in mid- to late summer to eliminate areas in which females would lay their eggs – which overwinter under the soil and hatch in the spring.
- Till the ground in late fall and/or early spring to destroy eggs that were laid the previous summer.
- Control and eliminate weeds in areas that are not sown to minimize feeding of newly hatched nymphs.
- For natural animal control, encourage grasshopper predators such as birds in and around garden areas.
- Cover grasshopper-preferred plants with cheesecloth to discourage feeding.
Chemical Control of Grasshoppers
When necessary, chemical bait and spray pesticides that are labeled for grasshopper control can also be used, reading and following all label directions. According Colorado State University Extension, however, baits and sprays need to be applied to developing stages of grasshoppers and concentrated at sites where egg laying occurs, as the ability to control grasshoppers declines as they develop and migrate.
Thus, such treatments should be focused on young grasshoppers and breeding sites during spring and early summer, depending on the geographic area.
The university also notes that adding canola oil to an insecticide spray can improve control by making the treated plants more attractive to the grasshoppers.
For a list of approved insecticides and general control, visit the university's page on Grasshopper Control.