Invasive balsam woolly adelgid detected in Roscommon County

Balsam woolly adelgid, a tiny, sap-feeding insect that attacks true fir trees, has been detected at the Backus Creek State Game Area in Roscommon County. The Michigan departments of Agriculture and Rural Development and Natural Resources have been managing isolated balsam woolly adelgid infestations in Clare, Missaukee and Oceana counties since 2023. A small infestation found in Kent County in 2021 is believed to be eradicated.   

The DNR manages the 4,378-acre Backus Creek SGA, located east of Houghton Lake for forestry and wildlife including waterfowl, upland game birds and deer, and the area is widely used by hunters.

Signs of a potential infestation were noted by a DNR forest technician in early March while conducting initial preparations for a prescribed harvest planned for 2028 to 2030.  

An insect sample was sent to the U.S. Department of Agriculture, Animal and Plant Health Inspection Service, then forwarded to Smithsonian Institution’s National Museum of Natural History, which provided final verification in late March. 

Why be concerned?

In Michigan, balsam woolly adelgid can infest species in the fir genus including balsam, Fraser and concolor (white) fir. The insect cannot feed on other trees or plants. The pest is on Michigan’s Invasive Species Watch List because persistent infestation weakens trees, kills branches and slowly causes trees to decline or die.

Symptoms of balsam woolly adelgid infestation include:

• Tiny, 1-to-2-millimeter, white, woolly tufts on the lower trunk of the tree and possibly on large branches.
• Swelling and distortion of the twigs, commonly called “gout.”
• Flagging – a branch or branches that turn brick-red and die.
• Tree crowns that become narrow and misshapen with few needles.

What is being done?

Forestry and Invasive Species Program staff from DNR and MDARD conducted a grid survey of the area surrounding the initial detection and identified several other pockets of balsam fir with light to medium balsam woolly adelgid infestation within the game area. 

Survey efforts will continue for a short time until balsam woolly adelgid eggs hatch and begin their crawler, or mobile, stage, when accidental movement on people, gear and vehicles is possible. Surveys will resume in the winter when the insect is no longer active. 

In Roscommon County, thus far the insect has only been detected on DNR property. If the survey area expands to include private property in the vicinity, owners will be contacted beforehand to request permission to inspect the fir trees on the properties.  

An MDARD quarantine now regulates the movement of all true fir (Abies species) within and outside of defined regulated areas in Michigan. As of 2024, regulated areas include parts of Clare, Missaukee and Osceola counties.  

An MDARD external quarantine regulating the movement of potentially infested nursery stock from areas in North America with known infestations has been in effect since 2014.

You can help

In Northern Michigan, the native balsam fir is often found in moist lowland forests with spruce and aspen. Although not native to Michigan, Fraser and concolor fir trees are often planted on home landscapes. 

Landowners, land managers and those who frequent the outdoors are encouraged to look for and report signs of balsam woolly adelgid. The fuzzy white ovisacs are most visible in the winter months. Adelgids are in the crawler stage in spring and summer, so anyone finding suspected infestations should clean clothing and gear as soon as possible to avoid spreading the insect to new areas. 

Reports can be made using the Midwest Invasive Species Information Network (MISIN) reporting tool or the MISIN smartphone app or by emailing photos and location information to MDA-Info@Michigan.gov.

Balsam woolly adelgid can be introduced on infested nursery stock, Christmas trees, firewood or tree products. Though the insects don't move far on their own, they can be carried by wind, wildlife, humans or vehicles to new locations.

• Don’t move firewood: Buy firewood at or near your destination to prevent the spread of invasive insects and diseases.
• Play, Clean, Go: After visiting Michigan’s forests and trails, take time to clean your vehicle, clothing and gear before traveling to a new location.

Find more information about balsam woolly adelgid on the Michigan Invasive Species Program website. Use the Invasive Species Watch List Viewer to see a map of known balsam woolly adelgid locations in Michigan.