The First North American Record of the Allium Leafminer

The invasive species Phytomyza gymnostoma (Loew) (Diptera: Agromyzidae), also know as the Allium Leafminer, is reported from the United States for the first time. The first specimens were collected in Lancaster County, PA, USA in December 2015. An additional 19 counties in Pennsylvania and two states were confirmed in 2016. The species' North American distribution, pest implications, and observations on their biology in the New World are reviewed.