Trap Cropping to Manage Grasshoppers
By Clint Burfitt, State Entomologist for the Utah Department of Agriculture and Food. Clint is co-coordinator of the Utah Cooperative Agriculture Pest Management Survey program, and manages the statewide grasshopper and Mormon cricket surveys.
Grasshopper infestations are difficult to predict, and over the years, have caused widespread damage to Utah's crop and rangeland habitats. Infestations are cyclic, occurring every 3 to 7 years. They can last up to 5 years depending upon environmental conditions such as food availability, weather, and presence of pathogens. When a community, neighborhood, or large area is experiencing the onset of a grasshopper infestation, it is best if landowners can communicate and coordinate treatments. Just treating a small part of an infested area will not be effective.
Treatment efforts should occur before grasshoppers become adults and begin mating (by early August in northern Utah and mid June in southern Utah). Before conducting any sprays or control efforts, applicators should contact nearby beekeepers and organic-certified producers to avoid negatively impacting their businesses. Ranchette developments and absentee landowners can complicate treatment efforts and often create situations where coordinated actions are not possible. In these situations, homeowners and agricultural producers can be subject to the nuisance and crop damage associated with large numbers of grasshoppers.
One treatment option that has been conducted successfully in Utah is trap cropping. One Hurricane farmer, who grows watermelon, planted rows of grains (wheat, triticale, and rye) early in the spring to serve as wind breaks for the watermelon crop. The grass borders, so long as they stay green, create a barrier between areas where grasshoppers hatch and where they prefer to feed. They are particularly effective in areas where there is a lack of attractive or green grasshopper forage in the surrounding areas.
As range or weed plants die down, grasshoppers migrate to feed on the grain strips. After the grasshoppers build in numbers in the border grasses, they are sprayed or baited to reduce the population. Treating trap crops reduces the amount of pesticides used on food crops and gardens, helps to protect beneficial and pollinator insects, and saves money.
Green borders as trap crops can also work in home gardens. Plants should be started early in the spring or late fall to protect crops or gardens from grasshoppers.
-Clint Burfitt, Utah State Entomologist