Invasive Species Report

recently in Benzie) on public and private lands along 100 miles of lakeshore (see map). A substantial amount of grant funds has been allocated to support survey and treatment work to manage HWA in West Michigan.

As one of seven counties in the West Michigan Cooperative Invasive Species Management Area (CISMA), Oceana County benefits from state and federal grant funds to treat targeted invasive species in forest and wetland areas. Oceana Conservation District works closely with the Ottawa and Muskegon Conservation Districts to implement invasive species treatments in Oceana County. Prioritization is currently going to species that are present in our county in relatively small or isolated populations but pose a high risk of further spread. An “early detection, rapid response” approach enables land managers to act quickly, before the species population grows to the point where it cannot be locally eradicated.

During the 2022 field season, CISMA crews treated approximately 48 acres of terrestrial invasive species on private and public property. Target species in 2022 included Japanese Knotweed, Japanese Barberry, Hemlock Woolly Adelgid, Oriental Bittersweet, Phragmites, European Frogbit, and Autumn Olive.

The West Michigan CISMA is closely monitoring and actively involved in managing Hemlock Woolly Adelgid and European Frog-bit that are prevalent in Oceana County. Updates are provided below.

Hemlock Woolly Adelgid

Hemlock Woolly Adelgid (HWA) is an invasive insect that has been identified in six West Michigan counties (Mason, Oceana, Muskegon, Ottawa, Allegan and most tive marsh vegetation, reduce native fish and wildlife populations, restrict access for boats and landowners , and can be a fire danger for nearby residents.

Locally, HWA has been detected within the Pentwater State Game Area, Charles Mears and Silver Lake State Parks, and on numerous private properties in Oceana County.

The HWA strike teams based out of the Ottawa, Muskegon and Mason-Lake Conservation Districts supplemented DNR work and treated 5,434 trees in Oceana County in 2022. In recent years, grant funds have been directed to northern counties, however new efforts are underway to secure more work in Oceana County in 2023.

West Michigan CISMA, surveys were completed in 2020 to determine the extent of the infestation within the Pentwater River Watershed. Crews have been implementing spot treatments in the Pentwater River over the last two years, covering 79 acres within the Pentwater State Game Area. A management plan for European Frog-bit was drafted in 2022 and Pentwater will remain a priority.

West Michigan is currently the only CISMA in the state treating European Frog-bit, highlighting it as a primary target in the coming year. Funding is available for surveys, treatment, and re-treatment on public and private land. Sabrina Butler, Invasive Species Technician at Muskegon Conservation District, is the current lead on this project in both Muskegon and Oceana counties. Please contact Muskegon Conservation District for more information and to apply for treatment.

Grant funds are available to treat Phragmites in and along Pentwater River and Pentwater Lake in 2023. Muskegon Conservation District is hoping to contact landowners in the Pentwater Watershed and connect them with funding to survey and treat this invasive species. To find out more and to sign up for treatments, contact Sabrina Butler, Invasive Species Technician leading Phragmites treatment in Oceana and Muskegon counties.

Purple Loosestrife

Purple Loosestrife, a perennial herb, is present in relatively small amounts compared to counties in Southern Michigan and residents are encouraged to manage it where found. It grows along roadsides and wetlands, establishing and replacing native vegetation which reduces native plant diversity and subsequently habitat value to wildlife. Conservationists have had some success with biological controls, namely the leaf-feeding beetle (Galerucella spp). However, this is not an eradication effort but rather a suppression that allows the invasive to become part of a wetland plant community with less harm to surrounding wildlife.

(HWA) secrete white cotton-like clumps as they feed on sap from hemlock trees. HWA can kill needles, shoots and branches.

European Frog-bit

European frog-bit, an aquatic invasive species, was first detected in Pentwater Lake in 2019. In coordination with the Department of Environment, Great Lakes and Energy, the Gun Lake Tribe, and the

Native to Europe, Africa and Asia, European frog-bit is an aquatic plant with small, heart-shaped leaves. Unlike similar aquatic plants, European frog-bit does not anchor its roots in the lake or stream bed but remains free-floating. Resembling small lily pads, three-petaled white flowers with yellow centers appear briefly between mid-July and mid-August. The plant quickly forms dense colonies or mats that prevent native plant growth, make movement difficult for ducks and large fish, and cause problems for boaters, anglers and swimmers.

Phragmites

Invasive Phragmites, also called common reed, is a warm-season perennial grass often found in ditches, swales, wetlands, and on stream and pond banks. These invasive grasses quickly replace na-

Spongy Moth (Lymantria Dispar), formerly known as Gypsy Moth, is predicted to continue its natural decline this year! After a large-scale outbreak that led to particularly extreme defoliation cycles 2020-2022, Spongy Moth populations are winding down. Spongy Moth outbreaks are cyclical, peaking approximately every seven to 10 years, which is good news for landowners and nature enthusiasts who need a break from the early summer destruction of these invasives. Population crashes are largely due to biological controls; Entomophaga maimaiga, a fungal pathogen found to be killing spongy moth caterpillars, and Nucleopolyhedrosis virus. These pathogens help limit the size and length of the outbreak and are now widespread across Michigan, actively reducing populations. Localized outbreaks are never out of the question however, so landowners should continue to look for and scrape egg sacks when located by mid-April before larvae begin to hatch.

Spongy Moth (Gypsy Moth)

Spongy Moth egg masses are typically teardrop-shaped and about 1-2 inches long. They are yellow-brown in color, felt-like in texture, and can be found in cracks of tree bark, on the underside of large branches, on fallen logs and rock piles, and on lawn furniture. Masses persist after the eggs hatch in May, turn white and develop holes or tears. Each mass can hold between 600 and 1,000 eggs, so every mass you remove drastically decreases your chances of severe infestation.