Box Elder County farmers have been spraying their fields in an effort to wipe out a tiny insect threatening grain crops. But the insecticide may be dangerous to wildlife and humans, state officials said.

The farmers are using the chemical Disyston in an effort to kill Russian wheat aphids, which can destroy winter grain before next year's harvest."People hunting in Box Elder County should not eat game animals displaying unusual symptoms such as muscular problems, immobility, convulsions or other irregularities," said Jay Roberson of the Utah Wildlife Resources Division.

Disyston is poisonous if swallowed, inhaled or absorbed through the skin. And fields sprayed with the chemical have been posted, Roberson said.

"Hunters and others are warned not to enter fields that are marked," he said, "and animals taken from the immediate vicinity of sprayed fields should not be eaten."

"People may get sick from eating affected animals," Roberson said, but there have been no known human deaths reported from such ingestion.

Ducks and geese feeding on sprayed winter wheat fields may be shot several miles from the treated area, he said, adding, "it's best to know the pattern of the animals you're hunting and exercise caution."

Hunters who have shot wildlife possibly suffering from Disyston poisoning are being urged to take the animals to the nearest Wildlife Resources Division office.

"The division would like specimens to determine the extent of any contamination of wildlife from these spraying practices," Roberson said.