Utah hay growers are battling outbreaks of two insects this summer. High numbers of Mormon crickets and grasshoppers are moving from rangeland into hayfields, forcing many growers to apply insecticides or face major yield losses.

USDA’s Animal and Plant Health Inspection Service (APHIS) estimates that over 1.5 million acres are infested in 18 counties, causing over $25 million in crop damage so far.

Over 99% of the infested acreage is rangeland, says Greg Abbott, an APHIS plant inspection and quarantine officer. He says damage to rangeland is minimal, but both insects also feed on alfalfa.

The crickets tend to move through fields in waves, traveling several miles from where they hatch. "Some of the hay has been cut, so the problem is over until the next wave moves in," says Abbott. "Some of the greater problems are around homes and gardens."

Mormon crickets are actually shield-back katydids, a type of grasshopper. "They look sort of like crickets, but they’re actually long-horned grasshoppers," says Abbott.

Conventional grasshoppers pose a bigger threat to hayfields than do Mormon crickets because they stay near where they hatch, he adds.

Mormon cricket populations tend to peak every 40 to 50 years, and infestations can last several years. Grasshopper numbers cycle about every 10 years, according to Abbott.