An invasive pest, originally from Europe (from Poland, I think), and brought to the northeastern U.S. by ship transport of foods. Active quarantines are being set up by many states.

I believe mine may be the first report from WV. I took samples to my local Extension Office.

This is indeed a threat. That's true, alliums don't usually bow down to anything! On reading more, it seems that these leaf miners were first identified in Poland in 1858, and have been very slowly taking over Europe. Reached the UK in 2004. Kind of remarkable that it's taken so long for them to get established here. Their life cycle and habits sound very similar to Squash Vine Borers. We don't import many alliums from Europe, though some of our onions do come from Spain. Most of our garlic comes from China where I don't believe the leaf miner has reached.

Mine is now quite a small garden. I can easily use row covers on my alliums in the suggested months--April/May and Sept/Oct, but it's just one more job to do--and it doesn't improve the look of the garden. And makes it that much more of a PITA to cut a little chives or bunching onions.

Oh great!

I already have sap sucking insects that damage my walking onions, tho for some reason, they leave garlic chives alone.

I thought a few damaged leaves would be no big deal, but then I saw what they really do. Hope they don't make it to my garden anytime soon.

Well I'm a looong way from any other gardens... and they found me. Looks like it's going to be a real pest.

Pesttracker (CERIS Purdue) has some useful, though very incomplete, info. Though it's been a few years since much survey work was done, these guys were detected in SE Pennsylvania in 2016. https://pesttracker.org/map/IOABBPA/2016.

Well they can now add southeastern WV. Also, I got my information about it from VA Tech, and the map shows nothing in VA either. Looks like it's quite out of date.

What's blank on the map is "no survey", and not "not found" so they're up to date, but just admitting that they don't have info for this year. That's true just about everywhere. That's why I called it very incomplete.