Dr. Christine Noronha with her new wireworm trap

Dr. Christine Noronha with her new wireworm trap. (Submitted by Agriculture and Agri-Food Canada)

A simple trap invented by an Island scientist "could be a major breakthrough" in fighting P.E.I.'s $6 million wireworm pest problem, says Agriculture Canada.

Wireworms are beetle larvae that dig holes in potatoes as they grow, making them unfit for sale. They live in the ground, putting them beyond the reach of insecticides sprayed on the surface. They're a problem across the country, although worst in P.E.I., Alberta and B.C., says the PEI Potato Board.

The new device is called the Noronha Elaterid Light Trap, or NELT. It's made with three pieces: a small solar-powered spotlight, a white plastic cup and a piece of screening to keep out the beneficial bugs.  

"It's a very, very simple, basic design," said trap inventor Christine Noronha, an Agriculture and Agri-Food Canada entomologist.

"I'm really happy about it, I think it's something that will be able to decrease the population [of wireworms]."

The trap was unveiled Monday at a wireworm information session hosted by the PEI Potato Board in Charlottetown.

'If you're having a big problem, you have to do something about it.' — Christine Noronha, Entomologist

Here's how Noronha's invention works: the cup is dug into the soil, so that the lip is level with the ground, and the spotlight, powered by a photo-cell, shines into it. 

This attracts the source of the wireworms, female click beetles, that emerge from the ground in May and June. Each of the beetles can lay 100 to 200 eggs that produce the destructive wireworm larvae.  

"They come towards the light. And as they come toward the light they fall into this trap," Noronha said.

The beetles drown in a few centimetres of water and a few drops of dish soap in the cup. 


A wireworm, left, is the larval form of the click beetle, right. Wireworms love to feed on P.E.I. crops such as potatoes and carrots. (W. van Herk courtesy of Agriculture Canada)

"I'd been thinking about it for years now, but it wasn't feasible for use in a farmer's field."

She said battery-powered lights or those plugged in to a generator would have been just too unwieldy.  

Lightbulb moment

"Then I was just walking through one of the hardware stores and I saw a solar-powered spotlight," she said. "And I thought this might work." 

Noronha carried out field trials for six weeks last summer. Ten traps caught more than 3,000 females in the plastic cups, preventing the birth of up to 600,000 wireworms, she said. 

"I was just amazed at how many beetles we caught in this trap." 

Noronha is encouraging farmers to make their own similar devices, to use them in grassy buffer zones where click beetle populations come from.

It's one more tool farmers can use in an integrated pest management program, she said.  

"If you're having a big problem, you have to do something about it." 

Island wireworm species are resistant to pesticides that work in other locations, and farmers have been trying a variety of natural methods to try to control it. 

Agriculture and Agri-Food Canada is trademarking the trap name and design, and is now looking for a manufacturer interested in mass producing the trap to provide to farmers. 

The Canadian Horticultural Council continues to research ways to control wireworm across Canada.