The elm zigzag sawfly (Aproceros leucopoda) is now established in several places in North America. This non-native forest pest can be a threat to elm species and hybrids and is capable of large defoliation events. Will it turn into a full-blown invasive species, or simply co-exist with native herbivores in natural and urban forests? At this point, we don’t know. A new review highlights elm zigzag sawfly biology, ecology, and management strategies in the U.S. (Image by Matthew Bertone, Ph.D., originally published in Oten et al 2023, Journal of Integrated Pest Management)