A second round of spraying for grasshoppers is planned for next week outside of Grantsville and in Rush Valley — areas that were not part of a spraying earlier this month.

“It’s as bad as it was last year,” said Linden Greenhalgh, Utah State University’s Tooele County Extension director and ag agent. “The numbers of grasshoppers have really come on.”

Nearly 4,000 acres are planned for the spray, though more ground is being added all the time. Irrigated ground — mostly alfalfa on the north side of Grantsville — and rangeland west and south of Grantsville, in addition to some land in Rush Valley are planned for the spray.

“Grasshopper development is very different this year — later and spotty,” Greenhalgh said. “They have also matured faster.”

More than 2,000 acres on the outskirts of Grantsville, primarily on the southeast side of town, were sprayed aerially using Dimilin over the Fourth of July weekend. Greenhalgh said that application seems to have worked.

“I looked at it [Tuesday] and I’ve seen a lot of deformed grasshoppers over there so it’s working and doing what it’s supposed to do,” he said.

Dimilin is ingested by the grasshoppers and affects their development by preventing the proper development of the exoskeleton.

The second spraying will use the contact spray Malathion, which is a broad spectrum pesticide. Greenhalgh said they’ll be spraying with Malathion rather than Dimilin because of the grasshoppers’ stage of maturity, in addition to the fact that the spray area includes a lot of irrigated ground and Dimilin can’t be used on irrigated ground.

“It’s a kill-on-contact, so they have to come in contact with it, whereas the Dimilin they had to ingest it,” he said. “But it’s a real safe pesticide. It’s what they use to kill mosquitos with. It can be bought in the store, it’s not a restricted use.”

However, it does kill bees, so Greenhalgh has been calling the bee inspector.

There are still some sprayers available for public use from the county, Greenhalgh said.

“There’s just a limited number of them, so you’ll just have to call,” he said, “I just barely had a call from someone who had five acres. We can’t fly a plane over five acres, so if they can get hold of the county sprayer or some other kind of sprayer and use Malathion, that’s the best thing they could do.”

Sarah Miley: swest@tooeletranscript.com