U.S. Sen. Gary Peters (D-Mich.) has reintroduced a bipartisan bill that would provide new money to deal with an old pest in Michigan cherry orchards.
An invasive fruit fly called the spotted wing drosophila first arrived in northern Michigan 15 years ago. Since then, cherries have gone from being a relatively hands-off fruit to grow, to requiring much more labor and insecticides.
“We continue to have a loss on our crops and extreme input costs trying to keep it at bay,” said Emily Miezio, a fruit grower and chair of the Cherry Marketing Institute board.
The tiny fly lays its eggs in soft fruit like cherries and blueberries, rendering the fruit unusable.
If passed, Sen. Peters’ bill, called the Spotted Wing Abatement Trust Act or the SWAT Act, would set aside an annual $6.5 million fund for spotted wing drosophila research for the next five years.
“Research that's done is not, unfortunately, done in just one sitting,” said Miezio. “It usually takes years and years of trial and error to come up with the best way.”
That’s been borne out at the Northwest Michigan Horticulture Research Center, a Michigan State University Extension research center focusing on fruit trees just outside Traverse City.
Nikki Rothwell, a research specialist and coordinator at the station, said they’ve experimented with releasing parasitic wasps to prey on the fruit flies. They weren’t able to recapture those wasps and assess the results as intended.
Then researchers found another wasp that they didn’t introduce.
“We knew that it was a predator or parasitoid of spotted wing drosophila that’s been found in multiple states,” Rothwell said.
A reliable, consistent source of funding could spur more research into that wasp, which might be valuable as spotted wing drosophila develop resistance to the insecticides farmers use to deter them.
“We haven’t documented [insecticide] resistance yet with spotted wing drosophila here in Michigan, but it has been documented in the west,” Rothwell said. “So if we don’t have insecticides to control this, what are other options? I think, probably, that’s in the back of a lot of people’s minds.”
Researchers also want to look at the possibility of sterilizing and releasing males, so no offspring are produced after the fruit flies mate. (Scientists temporarily eradicated a pest insect called New World screwworm by using this technique.)
But, Rothwell says, more money could be key to making that happen.
The SWAT Act was introduced in 2022, then reintroduced for a first time in 2023.
