Invasive Allium Leafminer - Located in Washington County, MD
Hello - I am contacting you from Hagerstown, Maryland and I have a plot at our community garden here. Allium Leafminer is an invasive species that targets allium plants (onions, leeks, & Garlic). To my knowledge there have been no prior confirmed cases in washington county, so I wanted to reach out and let you know that we found them in our garden this evening. Here is the research on this from Pennsylvania Dept. of Ag: https://www.agriculture.pa.gov/Plants_Land_Water/PlantIndustry/Entomology/Pages/ALLIUM-LEAFMINER.asp...
Washington County Maryland
These insects pupate in protected plant parts (bulbs, leaf sheaths) and a second
If you re-plant, a floating row cover can be used to exclude the adults in spring and fall when they are flying and searching for host plants. You found good information from the PA Department of Agriculture. Penn State University is also conducting research on this new pest and has very good information about it. https://ento.psu.edu/extension/vegetables/pest-alert-allium-leafminer