This is the season for ramps— those wild, garlicy leeks that grow in the Appalachian mountains. But ramps are under threat from an emerging pest, called the allium leafminer, which also attacks garden onions and leeks.
The allium leaf miner is a tiny fly that lays eggs inside the leaves of onions and leeks. The larvae hatch and chew through the leaves. They can kill onion seedlings, but they do the most damage on wild ramps, said Tom Kuhar, professor of entomology at Virginia Tech.
“There’s no doubt they seem to do really well on ramps,” Kuhar said.
Allium leafminers originated in Europe, then made their way to Pennsylvania about a decade ago. In 2021 they were first identified in Virginia, and though there isn’t much data yet on how prolifically they’re spreading, Kuhar said he’s seen signs evidence that they could already by spreading through much of Northern Virginia and southwest Virginia.
Traditionally, ramps were known mostly to people who grew up in rural Appalachia— but they’ve grown in popularity in recent years, and some believe they could be overharvested. The allium leafminer could also put ramp patches at risk, according to Kuhar.
“It certainly doesn’t help that something that already may have been overharvested a little bit, because it just is increasing in popularity,” Kuhar said. “And then now you’ve got this invasive pest that could limit it.”
He said the pest harms ramps, particularly their leaves, but it doesn’t seem to decimate the plants.
“I think what’s gonna happen more often than not is people are gonna get a little extra protein in their wild ramps,” Kuhar said.
So if you dig ramps, or harvest leeks or onions from your garden this spring, watch for a line of small white dots on the leaves—which could indicate the plant is infected with eggs of the allium leafminer.
Take a photo, and report the sighting to your local extension agent, so researchers can try to reduce the damage to gardens and wild plants.
