Natural Pest Controls Reviewed in Canada

Published online: Jul 24, 2018 Articles Nancy Russell
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Source: CBC News

A research scientist at Agriculture Canada in P.E.I. is looking for natural ways to deal with pests that cause damage to cabbage, canola and potatoes.

Entomologist Christine Noronha has planted multiple plots at the Harrington Research Station this summer.

In the canola plot, Noronha and her team are studying tiny black beetles known as pollen beetles, an invasive species from Europe. They lay their eggs in the canola buds and then larvae eat the pollen inside the buds.

"They're in Quebec and in P.E.I. and all the climate models are showing that because of climate change they're going to be moving into Western Canada," Noronha said.

"Western Canada, they grow a lot of canola so they're concerned about this pest so because we have it here, we've decided to be proactive and we're starting to do some studies on this pollen beetle."

Tiny pest, big problem

Sealed white cages are placed over the canola plants and then pollen beetles are placed inside.

This tiny pest causes damage to canola buds. (Randy McAndrew/CBC)

"We're going to put certain numbers into these cages, five beetles per plant or two beetles per plant, [and see] which ones cause the most damage and yield reduction."

A nearby plot is filled with smaller white canopies placed over cabbage plants.

"In this field we are studying an insect called the diamondback moth, it lays its eggs on cabbage," Noronha said.

"The caterpillars hatch and they start eating the cabbage plants and they make big holes, they're a huge huge pest." 

Moths resist insecticides

The diamondback moth is very difficult to control worldwide, Noronha says, because they become resistant to any insecticides.

Students working for Agriculture Canada this summer weed the cabbage plot here at the Harrington Research Station. (Randy McAndrew/CBC)

"Here, what we're looking at is the presence of natural enemies or biological control agents," Noronha said.

"We know there are some very tiny wasps, they lay their eggs in the larvae and the pupae of the diamondback moth."

Noronha is excited to have found these so-called natural enemies here on P.E.I.

"So far, we have found five different wasps that are new to P.E.I. and one is actually new to North America," Noronha said.

"This research will be very important to any cabbage grower, cauliflower grower. This pest is a problem to all those crops."

Threat to potatoes

One of Noronha's key areas of research is how to prevent click beetles and wireworm that are extremely harmful to P.E.I. potato crops.

The caterpillars of the diamondback moth hatch and then eat the cabbage plants and make big holes. (Randy McAndrew/CBC)

This year, Noronha is combining several methods including a trap she has created called the NELT, or Noronha Elaterid Light Trap.

"The adults are attracted to this light so they are attracted to the light and then they fall into the glass and the glass has a liquid in it with a few drops of dish soap and then they drown," Noronha said. 

Christine Noronha holds a corn plant with wireworm in its roots. She is using a two-pronged approach this season to try to reduce populations of click beetles and wireworm.

In the next field, the research team has planted buckwheat, which is known to reduce the wireworm population.

"So now we're using a two-pronged approach, trying to get rid of the females from laying their eggs and we're also trying to kill the resident wireworms that are in the ground," Noronha said. 

The canopies cover cabbage plants that are part of a study on wasps and the diamondback moth. (Randy McAndrew/CBC)

"It's very important because we are having a big problem with wireworms on the Island and it's not only on the Island, it's world wide so we have to somehow control them."

Noronha has been working to reduce wireworm for almost a decade now.  

"You can never eliminate them but if you reduce the population to manageable levels, that's what everybody wants," Noronha said.