Garlic crop damaged? Leek moths may be to blame

By Meghan Groff

CityNews 95.7's The Weekend Gardener Niki Jabbour says she's received several photos from those trying to figure out what is ruining their garlic crop.

According to Dr. Suzanne Blatt, a research scientist at the Kentville Research and Development Centre, leek moths may be to blame.

The invasive species made its way to Canada from Europe and was first identified in 1993 in Eastern Ontario.

They arrived in the Maritimes by 2008 when they were spotted in Prince Edward Island. By 2016, reports of leek moths popped up in Nova Scotia and their presence was confirmed the next year.

“They will go after anything in the allium family, so that's your garlic, leeks, chives, shallots, scallions, onions … but they'll also go after the ornamentals,” Blatt told Jabbour on her Sunday morning radio show.

Blatt said the moths are speckled brown and white, and they're small — less than a centimetre in length.

“It tends to be very active at night or early in the morning, so often as a grower, as you're out working in our garden, you won't really notice you have the adults. You're more likely to see the damage that the larvae cause,” Blatt explained.

Milder winters are helping leek moths gain a foothold here and spread more rapidly.

Blatt said they overwinter as pupae, which some Nova Scotians may have noticed in their gardens.

“It looks like a grain of rice that's wrapped in a beige, fishnet stocking,” she said. “And that will be on the lengths of the green, so the scapes of the garlic or the chive, they will be on that length of the stem.”

They feed inside the stems, which causes what's called windowpaning, “so it looks like someone took the leaf and scratched it,” Blatt stated.

The pupae become adults by April, which is considered the first flight, giving the species time to produce a second flight over the summer.

She said plucking off damaged parts might reduce the population of leek moths in your garden. Using row covers in the early spring can also help, unless the crop is already infested, then you're just caging them in.

Blatt also suggested, if you've got the room, try moving your allium crops to a different patch in your garden.

“For that early flight, there is a bit of a preference that leek moths will have and they really quite like chives,” she added. “If you plant chives near your leek or your garlic, they will tend to lay their eggs there.”

“So if your chives were in a pot, you could just remove that pot and then you'd be able to deal with whatever eggs or pupae are on there and you'd prevent the second flight, or the second flight would not be as high.”

The Weekend Gardener Niki Jabbour can be heard every Sunday throughout the season from 10 a.m. to noon on CityNews Halifax.

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