Leek moth poses threat for garlic, onion growers on P.E.I.

An invasive species that attacks leeks, garlic and onions could become a big problem on Prince Edward Island.

The leek moth is a tinybrown insect that likes to feed on a class of vegetables known asalliums, and it can cause a lot of damage.

Al Picketts, agarlic farmer in central P.E.I., said he isconcerned the pest will wipe out his crops someday.

"When they can find garlic, they just destroy the crop," he said."Soit's just going to be the end of you growing garlic."

Picketts said other farmers on the Island have dealt with the moth in recent years, and the pest has done a lot moredamage to crops in other provinces.

"The leek moth could be a major setback for growing garlic here and how you get rid of it, I have no idea," he said.

The larval form of the moth willeat through the plant, preferringto feast on leeks and larger and healthier plants. Small exit holes may be spotted after the larvae grow into moths and fly away from the eaten-out part of the plant.

At that point, an adult moth no longer poses a threat to a plant.

Picketts said the larvae can be identified by orange or red dots on their back, but they are very small and difficult to see. Thatcan create problems when it's time to sellthegarlic.

"I would expect a consumer might not be very happy if theyopen up a garlic bulb and find two or three big worms in there," he said."Not only does it damage your crop, it damages your credibility. And there's not really any way you can prevent that... It's not something that you've done wrong, it's just that the worm has away of infiltrating the bulb."

Picketts plans to spray a non-chemical product containing Bacillus thuringiensis(or B.t.)next spring to help keep the moth away. That type of bacteria produces aprotein crystal that will kill the leek moth when it's still in thecaterpillar stage. However, it can be expensive and washes away easily if there's rainshortly after it's been applied.

Leek moths like warmer weather

Christine Noronha, a research scientist with Agriculture and Agri-Food Canada, said the leek moth has been on the Island for over a decade, but has done more damage in the last few years.

One reason could be the warmer spring and summer temperatures P.E.I. has been experiencing.

"When you start to see temperatures go up, the number of generations can start to increase," she said. "Usually, it's just one generation. If it's a cool summer, you have one generation.

"But when you start to have really warm summers, than you start to have two generations. And then wherever you have a second generation, there's more numbers and they cause more damage."

If the winter is warm and doesn't kill off many of the overwintering moths, Noronhasaid the invasive species can cause a lot more harm to cropsin the following spring and summer, since thepopulation will be larger.

She agreed the moth has the capacity to kill a large percentage of a crop if a field is infested.

"If no control methods are used and the population has two to threegenerations, then yes, there is a potential."

If you have a small garden, Noronhasaid you can simply crush any moth eggs you spoton your garlic or onions. People withlargefarms can use row covers, made of a light material that covers the plant, to prevent the moths from laying eggs in the spring.

She also suggests using leek moth traps in the spring to find out if the pest is on your crops, to determine whether you need to take action.

"It's here to stay, it's not going to go away, so we need to just control it," she said.