Press Release  DCR Announces That Elm Zigzag Sawfly has been Confirmed in Massachusetts

Boston — The Department of Conservation and Recreation (DCR) today announced that DCR Forest Health staff have detected elm zigzag sawfly (Aproceros leucopoda) for the first time in Massachusetts.  

Agency staff identified defoliated elm trees in Becket and after an investigation confirmed the damage was caused by elm zigzag sawfly. Since the original detection of the invasive species, populations have been found in Berkshire and Hampden Counties. At this time, staff have not yet determined how the species was introduced to Massachusetts. DCR foresters are working to identify the extent of infestation in the state.    

The elm zigzag sawfly is native to Asia and was first reported in North America in July 2020 in Sainte-Martine, Quebec, Canada. Since then, it has been confirmed in seven U.S. states, Virginia, Pennsylvania, New York, Massachusetts, North Carolina, Maryland, and Vermont. Elm zigzag sawfly larva feeds upon elm trees (Ulmus spp.) and can be identified by the eponymous zig-zag pattern damage. The larvae are small, pale green, and caterpillar like. Once mature, they will spin a net-like cocoon on the elm leaves to pupate, eventually emerging as a winged adult sawfly.  

Homeowners should direct reports of possible elm zigzag sawfly activity to the DCR Forest Health Program and contact a certified arborist to discuss treatment options for their elm trees. To learn more about elm zigzag sawfly and other forest health threats visit the Massachusetts DCR Forest Health Program (arcgis.com) storymap.  

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