NORTON SHORES, Michigan (WOOD) — Norton Shores park officials have arranged two treatments for a coastal park dealing with an invasive species.
Brian Clark, de Norton Shores Parks & Recreation Superintendent, told News 8 that pesticide treatment will begin this fall at Lake Harbor Park to treat hemlock trees infested with the hemlock woolly haired adelgid.
Drew Rayner leads the Michigan Department of Natural Resources’ fight against the tiny bug in West Michigan. He said that the insect cannot move quickly on its own, but has managed to extend over five different provinces after he was first spotted in 2015.
“It now only exists from Allegan County to Mason County. So we really have an area of about five counties and it really hugs the coastline,” Rayner told News 8.
The hemlock woolly adelgid spreads mainly by hitchhiking on other animals and people.
“There are many vectors,” Rayner said. “Animals can spread them; birds and wildlife can pick up crawlers. We have caterpillars from spring to early summer that we won’t really be able to see (when) people and animals brush against the branches of an infected tree.”
The most common sight is not the insect itself, but what it produces.
“When HWA feeds, it produces a white ovisac, a small white, fluffy mass. You’ll see them lined up right at the bottom of the needle,” Rayner said. “It’s easiest to turn some branches a bit and look at the underside of the branches. … It’s pretty easy to spot.”
Because the HWA takes nutrients from the trees, the hemlocks stop growing and the needles take on a grayish hue. But with treatment, the insects are killed and the trees can recover.
There are two treatments to kill HWA: one that can be applied to the tree bark and another that is sprayed at the base of the tree and absorbed by the roots.
The bark treatment is effective, but it takes a long time to stick. The soil moistening works quickly, but wears off quickly and can lead to chemicals being released into the groundwater, depending on the soil content.
“There are basic bark applications where you mix the chemical in a sprayer and apply the chemical to the bark. It’s pulled in through the bark and moved to the tree,” Rayner said. “And then soil moisteners mix the chemical with water and it’s poured at the base of the tree. We’ve tried to stay away from soggy soil here in Michigan because we have some really sandy soil along the shoreline. … It really depends on the condition of the tree.”
According to the DNRMichigan is home to more than 100 million mature hemlocks, which provide important habitat and cover for wildlife during the winter.
Work on Lake Harbor Park is expected to begin in September. The crews will start with 28 acres of land near the southern part of the park. The crews will return next year to cover an additional 39 acres on the northern half of the park.
This fall’s work is expected to cost about $28,000. According to Clark, funding was secured during the annual budget process in May.
If you see a tree that you believe is HWA infested, do not remove the material. The DNR asks you to take photos and note the location of the tree, then pass the information on to the agency. You can learn more about HWA at: the website of the DNR.