by Steve Garske, Invasive Species Coordinator
In mid-April GLIFWC staff met with Wisconsin Department of Natural Resources Forest Health Team Leader Rebecca Gray in New Odanah. Gray detailed what the DNR was doing to address problems resulting from the influx of non-local beings, and to talk about ways that GLIFWC and the state can work together to minimize the threats they pose to local beings and their habitats. Topics ranged from a DNR-supported remote sensing project to locate emerald ash borer-resistant ash, to the non-local beings that threaten the health of the region’s forests.
Since the arrival of the emerald ash borer (EAB) in solid wood packing material three decades ago, more than 100 million ash trees have been killed across the eastern half of the United States, disrupting ecosystems and causing billions of dollars in damage. In an attempt to reduce the impact of this insect, state and federal agencies have focused mostly on releasing four tiny parasitoid wasps (whose larvae feed on and kill EAB eggs or larvae), and on finding individuals or stands of ash that appear to be resistant to the EAB, then collecting seeds or cuttings from them to use in breeding programs.
The Wisconsin DNR is working with the US Forest Service Northern Research Station in Ohio to test the resistance of black and green ash strains from their breeding program. Seedlings from this program are scheduled to be planted at the DNR’s Griffith State Nursery in Wisconsin Rapids soon. The goal is to plant as many resistant strains of black ash as possible. Once ash mortality has progressed to the point that lingering black ash can be detected in northern Wisconsin, these will be brought into the breeding program as well. While similar screening trials are likely to be implemented for resistant aagimaak (white ash) and emikwaansaak (green ash), finding and breeding resistant baapaagimaak (black ash) is a top priority for the DNR’s tree improvement program.
Part of the discussion dealt with non-local beings that are just moving into the Ceded Territory, or that are likely to arrive in the next several years. A particularly colorful introduction is the spotted lanternfly (scientific name Lycorma delicatula). First found in Pennsylvania in 2014, this leafhopper-like insect has spread to at least 18 states including Lower Michigan. Adults are up to one-inch long, with a 1.5-inch wingspan. The juveniles (nymphs) and adults feed on plant sap. Hosts include maple, willow, poplar, and many types of fruit trees. But their favorite foods are grape vines (Vitis spp.) and tree-of-heaven (Ailanthus altissima). While feeding they excrete a sticky, sugary fluid that sticks to plants and anything else it drops onto. Both tree-of-heaven and the spotted lanternfly are introduced from Asia.
Spotted lanternfly females behave similarly to spongy moth (Lymantria dispar, formerly known as gypsy moth) females, in that they lay large, irregularly-shaped egg masses on just about any hard surface including outdoor furniture, vehicles, camping equipment, and firewood. In this way they effectively enlist unsuspecting humans into helping them spread. This insect is all but certain to show up in the Lake Superior region - it’s just a matter of time. It is hoped that the region’s colder climate and the near-absence of tree-of-heaven will keep its numbers relatively low.
Gaagaagimish (eastern hemlock) is also threatened by non-local beings. The hemlock woolly adelgid (Adelges tsugae, or HWA for short) is native to central and eastern Asia and the Pacific Northwest. Within this range the adelgid is only a minor problem for its hemlock hosts, which are naturally resistant to it. Eastern hemlock has little natural resistance to the HWA though, and natural HWA predators are absent from its range. So when a HWA lineage from Japan showed up in Virginia in 1951, the writing was on the wall. Since then the HWA has spread through much of the eastern hemlock’s range, as far west as western Lower Michigan. Along the way it has caused extensive hemlock decline and mortality.
Unfortunately, the HWA is also likely to show up in the Lake Superior region at some point.
Another hemlock-feeding insect is also established in the eastern US, and is headed west. The elongate hemlock scale (Fiorinia externa) belongs to a group of aphid relatives called “scale insects”. They suck the sap from the needles of the tree, and deposit hard wax on their surfaces. First found in North America in New York in 1908, it has been slowly spreading west, reaching southern Lower Michigan by 2010. While these insects are not as much of a threat to hemlock as the HWA, they can weaken the trees, and heavy infestations over several years can even kill them.
Meanwhile oak wilt continues its decades-long advance into northern Wisconsin. This fungal disease clogs the water-conducting tissue of oak trees, starving them of water and nutrients. Oaks in the red oak group including mashkode-miizhimizh (red oak) and pin oak are usually killed in a month or two, while those of the white oak group (bur oak, swamp white oak, and white oak) may persist for years, and mitigomizh (white oak) may even recover. Because the beetles that spread the spores are only out through mid-summer, the best thing people can do to avoid spreading oak wilt is to not cut or prune oak trees between April 15 and July 15 (or better yet, August 1). See https://dnr.wisconsin.gov/topic/foresthealth/oakwilt for more information.
Other overseas introductions include the viburnum leaf beetle and cottony ash psyllid. The larvae and adults of the viburnum leaf beetle (Pyrrhalta viburni feed on the leaves of aniibiminagaawashk (highbush cranberry) and other viburnum species. The beetle prefers plants that are in shade, and shrubs in full sun seem to be mostly spared. (Look on shaded lower branches for damaged leaves.) The cottony ash psyllid (Psyllopsis discrepans) feeds on the sap of black ash leaves, causing them to pucker and curl, and eventually fall off the tree. For more on these two beings, see the Niibin (Summer) 2023 and Biboon (Winter) 2023-2024 issues of the Mazina’igan, respectively.
Finally, the Asian longhorned beetle (Anoplophora glabripennis, or ALB) is a major threat to North America’s forests, orchards and landscape trees. This insect first showed up in Brooklyn, NY, in August 1996, before wood packing material regulations were enacted. Since then, this infestation and others in Chicago, New York City and outside Toronto, Ontario have been eradicated. Eradication efforts continue in Long Island, New York, Massachusetts, Ohio and South Carolina. The ALB tunnels through the wood of a wide variety of tree species, weakening and eventually killing them. Its favorite trees are maples, including ininaatig (sugar maple). See https://www.aphis.usda.gov/plant-pests-diseases/alb .
Get the word out
The US Department of Agriculture - Animal and Plant Health Inspection Service Plant Protection and Quarantine program (USDA-APHIS-PPQ) is responsible for preventing the introduction, establishment, and spread of animal and plant “pests” and diseases and invasive plants to the US. The agency routinely intercepts destructive invasives such as the Asian longhorned beetle. Unfortunately, ongoing cuts to the USDA are likely to negatively impact its ability to stop the introduction and spread of non-local species that impact forests and crops. This makes early detection and rapid response by individuals and tribal, local and state agencies even more critical!
If you happen to come across any of these insects (except the white-spotted pine sawyer), take a few good photos and/or gather some samples (in a sealed container), note the location and report it! You can contact your area tribal natural resource department, or contact GLIFWC at steveg@glifwc.org or at 715-682-6619 ext. 2126.
You can also report your find to the state agencies. In Michigan, call the Michigan Department of Agriculture and Rural Development (MDARD) at 800-292-3939, or email them at MDA-Info@Michigan.gov. In Wisconsin, call DATCP at 866-440-7523, or email Renee.Pinski@wi.gov . (You don’t need to report EAB sitings in Michigan, or in areas of Wisconsin where EAB is already known.) The future of the region’s forests depends on it!