While the current anticipated outbreak of spongy moth is alarming to witness and does cause stress to many trees, long-term management of this species and our urban forest requires a broad focus. Unfortunately, the spongy moth is well-established throughout most of Wisconsin. From a statewide and nationwide perspective, it is critical to direct resources at stopping the spread of this species to new areas that have not yet been infested. The Wisconsin DNR Spongy Moth Portal provides more information on the management of the species at this broader scale.
In Madison, dealing with occasional peaks in the spongy moth population requires a holistic approach – and fortitude. Unlike Emerald Ash Borer, the spongy moth is a pest that is not necessarily lethal to trees. Most feeding damage is done in June and July. Healthy trees typically recover, sprouting new leaves and continuing to grow long after the caterpillars turn into adults.
In Madison's parks, we are working to provide the best conditions we can to ensure that trees remain healthy. This includes removing non-native tree and shrub species from woodlands, thinning taller trees around oaks to reduce shading and competition, and pruning oaks only during the fall and winter to prevent spreading diseases like oak wilt. We are also changing our mowing practices to reduce soil compaction under oak trees in more open areas.
This is all part of integrated pest management (IPM), which seeks to help desirable vegetation grow as healthy as possible, to maximize its natural resilience to pests and disease. IPM also seeks to use pest control methods that have the lowest possible impact on humans and the environment. Sometimes this involves tolerating non-lethal pests and focusing on cultural practices that will minimize the overall impact of those pests.
On a citywide scale, it is not feasible for Parks to control spongy moths directly on individual trees or in localized outbreaks. We are working to maintain and improve the health of oaks throughout the park system. The City of Madison Engineering Division is recruiting volunteers in one focus area. See City Asks For Volunteers to Help with Spongy Moth Outbreak.
Are you interested in volunteering for Madison Parks? See Volunteer Projects for opportunities.
This content is free for use with credit to Madison Parks and a link back to the original post.