Grasshopper populations low in Utah, but homeowners should stay prepared

SALT LAKE CITY — One of the most feared garden pests in Utah is the grasshopper, which can severely damage landscapes, gardens, and agricultural crops. Six or seven grasshopper species regularly cause economic damage in the state.

With Utah's unusually mild winter, there was concern that grasshoppers would be especially damaging this year. Instead, across much of the state, their numbers have been surprisingly low.

Why? The answer isn't clear.

Linden Greenhalgh, a Utah State University extension agronomist with extensive experience in rangeland grasshopper control, said grasshopper populations can fluctuate dramatically from year to year. In Tooele County, he has observed a roughly seven-year cycle in which populations gradually build, reach damaging levels and then crash. He said the last severe grasshopper year in his area was 2024.

Greenhalgh also noted that predicting grasshopper infestations is far from an exact science. Many factors influence grasshopper survival, including food availability, weather during egg hatch and nymph development, predator populations, and disease-causing pathogens. Because these factors interact and are difficult to monitor across large areas, grasshopper populations do not always behave as expected.

Grasshopper mitigation

Even though it is difficult to predict when grasshopper populations will reach damaging levels, there are several steps homeowners can take to reduce problems on their property.

In the fall and again in late spring, remove weeds and plant debris that can provide food and shelter for grasshoppers. Where appropriate, shallow fall cultivation in areas where grasshoppers may have laid eggs can expose or disrupt egg masses, potentially reducing the number that survive until spring.

During the growing season, particularly in rural areas, maintaining a vegetation-free or sparsely vegetated buffer several feet wide around gardens may also discourage grasshoppers from moving into the area by reducing available food and cover. While grasshoppers can readily cross bare ground, reducing vegetation immediately surrounding a garden can make the area less inviting.

Regular monitoring is also important. Grasshoppers readily feed on many garden plants, including carrots, onions, corn, green beans and melons, as well as flowers such as zinnias, marigolds and cosmos. Monitoring these and other susceptible plants can help detect increasing grasshopper activity before damage becomes severe.

If treatment becomes necessary, focusing control efforts along garden borders and other areas where grasshoppers are concentrated may reduce the need for widespread pesticide applications. Treating grasshoppers while they are young is generally more effective than waiting until they are large adults.

Several insecticides and baits are available for grasshopper management, but homeowners should select products carefully based on where they will be used. Products applied to vegetables and other edible crops must be specifically labeled for those plants, and required intervals between application and harvest must be followed. Always read and follow pesticide label directions.

Although grasshopper populations are relatively low across much of Utah this year, their cyclical nature means they will eventually increase again. Good sanitation, reducing favorable habitat, regular monitoring and early intervention can help homeowners prepare for the next time grasshopper numbers begin to climb.

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