Spotted Lanternfly confirmed at multiple locations across the watershed

Spotted Lanternflies (Lycorma delicatula) have been confirmed at multiple locations across the watershed over the past two months — 28 iNaturalist observations from Watertown, Cambridge, Newton, Arlington, Brookline, and Waltham, with four logged in the past two days. These are presence records reflecting where observers have reported the species, not a measure of population size or density.

This planthopper, native to China and Southeast Asia, arrived in Pennsylvania in 2014 and has spread steadily north. Its preferred host is tree-of-heaven (Ailanthus altissima), itself an invasive that has colonized disturbed ground throughout this area — a ready-made food source. Adult lanternflies feed on the phloem of a wide range of trees, including maples, oaks, black walnut, and wild grape, depleting carbohydrate reserves and excreting a sticky honeydew that coats leaves and encourages sooty mold. If you spot one, report it on iNaturalist.