TAWAS CITY — Two experts from the Michigan State University Extension (MSUE) weighed in on the potential chemical treatment of gypsy moths in the Hale Area during the Feb. 19 meeting of the Iosco County Board of Commissioners.
The upshot of the opinions of MSUE Consumer Horticulturist Sarah Rautio and District Forester Eric Brandon, was that the county should hold off on spraying and let natural predators take care of the caterpillars.
Back in April of 2019, commissioners voted to hire Aquatic Consulting Services of Sanford will conduct a study at a cost of $8,567 to determine if spraying for the caterpillars and moths will be needed in the future.
Rautio said in her expertise, the county should wait to spray and allow an introduced fungus, that kills the caterpillars, come in and do the job.
Rautio gave a history of the caterpillars and moths, and why they are so hated and what they can do to live trees.
“The history is we had them come into the state in the 1990s and they because quite an issue in this area,” he said. “At that time we didn’t have any natural predators, they exploded, they lay their eggs and the larvae feed on the leaves of trees.”
If the tree is unhealthy to start with, the infestation can lead to killing the tree, but a lot of trees survive. Rautio said that several years ago a fungus was released, which will kill the caterpillars, and it has proven to be successful.
“It seems to be one of the top predators and the fungus hits when we have a wet spring,” she said. She said in other areas of the state, to see the fungus really get into action, the caterpillars have to have an “up” year where there are large numbers, then the fungus takes charge and wipes out the caterpillars naturally.
“The predator kicks in about two years after the prey get up, we have seen these gypsy moth numbers go up, so now we have to wait for a couple years to kick in,” she said. “I want people to be aware of the fact that we do have some natural controls out there, but it doesn’t mean you can’t consider a spray program, it’s just determining whether or not you think it’s necessary.”
She said from a homeowner standpoint, they can use a home spray that has a biological agent in it, one that is safe to humans, but it will kill other types of caterpillars, not just gypsy moth caterpillars.
Brandon spoke next and said that he had read through the report and was confident in his years as a forester working for various agencies, that the survey was sound.
“Should we spray or not to spray? That is the big question,” Brandon said.
He said that he would advise people to wait to see if the gypsy populations crash.
“I’d say wait to see. Let the fungus build up again,” he said “I think this is the year to wait and see.”
Commissioner Terry Dutcher asked if the county did spray, what kind of effects could it have and would it do harm to anything else.
As Rautio explained earlier, she said that the spray kills caterpillars, including the gypsy moth caterpillars, but it targets a receptor in caterpillars and can kill other species, including the monarch butterfly caterpillar.
Commissioners were not keen on potentially harming monarch butterfly areas. Another concern was overspray on to federal land areas, which could occur. Brandon told commissioners that they would need an overspray permit, and if the county wanted to spray federal land it would need an act of congress.
County co-administrator Mindy Shirmer said spraying in the spring may be a moot point for the county, however, as there isn’t budgeted funding to do the spray right now.
“We don’t have the dollars to do the spring spray, but we can inform people that they can do the small areas, so we have to see what is going to happen in the fall anyway,” she said.