03/23/2026
Request for Comments: Proposed Rescission of MDARD’s Chestnut Gall Wasp Quarantine
MDARD Press Release
The Michigan Department of Agriculture and Rural Development (MDARD) is asking Michigan stakeholders to provide comments on a proposed rescission of the state’s Chestnut Gall Wasp Quarantine by 11:59 p.m. ET on April 10, 2026.
Michigan’s Pest Risk Analysis and Proposed Action
To ensure that regulatory decisions remain aligned with current science, MDARD recently completed a pest risk analysis for chestnut gall wasp (Dryokosmus kuriphilus), a species regulated under Michigan’s exterior quarantine program since 2010. This analysis was conducted using a standardized framework that considers factors such as potential for establishment and spread, as well as economic and environmental impact.
Based on this assessment, chestnut gall wasp was assigned a rating of low concern. Although chestnut gall wasp has become widespread in Michigan, growers have developed integrated pest management strategies to manage the insect. Rescinding the quarantine would enable MDARD to focus its resources on higher risk invasive pests while reducing the administrative burden for growers and nurseries.
Background
The Asian chestnut gall wasp (Dryokosmus kuriphilus Yasumatsu), an insect native to China, is a major invasive pest of chestnut trees in Japan, Korea, much of Europe, and the United States. In high densities, chestnut gall wasp can reduce tree growth and nut production. In 2010, MDARD implemented a proactive exterior state quarantine to prohibit the importation of all live
Castanea nursery stock and scionwood from infested regions unless the stock was certified that the origin nursery was a pest free place of production.[1]
Despite this precaution, chestnut gall wasp was first identified in two southwest Michigan orchards in July 2015. The pest has since become established in all chestnut producing counties in Michigan, including Allegan, Barry, Berrien, Calhoun, Cass, Kalamazoo, Kent, Ottawa, St. Joseph, and Van Buren counties.[2]
MDARD has continued to enforce the quarantine provisions. Complementing state-level measures, university researchers are monitoring the pest and evaluating control methods to manage chestnut gall wasp populations in orchards.
If rescinded, all restrictions on domestic trade of the regulated articles (living plants and scionwood of all Castanea spp., including hybrids) and regulations associated with the Chestnut Gall Wasp Exterior Quarantine would be lifted. MDARD assesses that rescinding the quarantine poses no risk to human health in Michigan.
Public Comment Invitation
As MDARD considers rescinding the chestnut gall wasp quarantine, MDARD invites comments from the industry and the public. We value your input and encourage you to share your thoughts and concerns regarding the proposed rescission. MDARD is committed to engaging with chestnut growers and the broader public, and we will carefully consider all comments received before making a final decision.
Submit Public Comments at https://forms.office.com/Pages/ResponsePage.aspx?id=h3D71Xc3rUKWaoku9HIl0c8YV5zjfwNBqEZrPtgU4zVUN0lVUjc4VDQzRDJaVEpPUThDODRSOE5NSi4u
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[1] Michigan Department of Agriculture. (2010, May 17). Chestnut gall wasp quarantine. State of Michigan. Retrieved from https://www.michigan.gov/mdard/-/media/Project/Websites/mdard/documents/pesticide-plant-pest/planthealth/chestnut_gall_wasp_quarantine.pdf?rev=6adf45ba9bc14586918021bb4b937593&hash=A83E3271758BC9316304BDC24C7DBF7.
[2] Labbate, L., & McCullough, D. G. (2021). Asian chestnut gall wasp: An invasive pest of concern for Michigan chestnut growers. Michigan State University. Retrieved from https://www.canr.msu.edu/chestnuts/uploads/files/E3464_Asian_Chestnut_GW_%202021.pdf.
