Andrea Hitchons
Andrea Hitchon

Helping to keep Ontario’s corn crop free of the “billion-dollar bug” is the goal of research by master’s student Andrea Hitchon.

She aims to prolong the effectiveness of Bt corn for controlling rootworm, a major corn pest estimated to cost more than $1 billion a year in control costs and yield loss in North America.

For her degree in plant agriculture based at U of G’s Ridgetown Campus, she’s monitoring corn rootworm for signs of resistance to genetically modified corn. She hopes to improve current monitoring methods and help growers learn about best management practices to delay resistance.

Farmers using this corn need not use soil insecticides for rootworm control, says Hitchon. “It’s a significant savings to growers if they can use this technology and it also saves them time.”

Bt corn contains a gene stitched in from a soil bacterium that prevents the rootworm larvae from feeding on the plant roots. It controls both types of rootworm found in Ontario. The pest has devastated crops in the American Midwest, where the Western corn rootworm has developed resistance to Bt varieties.

So far, those varieties have held out against the insect in Canada. But, says Hitchon, “There’s no reason it couldn’t happen in Ontario.”

For her degree with plant agriculture professor Art Schaafsma, she’s helping to monitor for the pest and ensure that it hasn’t developed resistance. This is her third season on the project, working with Jocelyn Smith, a Ridgetown research associate, and Tracy Baute, an entomologist with the Ontario Ministry of Agriculture and Food, also in Ridgetown.

Also involved are industry partners and the Canadian Corn Pest Coalition.

They look at 10 sites each year in southern Ontario within about a three hours’ drive from Ridgetown, as far as Pickering and Kincardine. They also respond to cases of suspected resistance reported by growers, extension workers and industry representatives.

They target fields where resistance is more likely — lots of rootworm, uninterrupted corn cultivation and use of the same Bt trait.

The researchers collect thousands of beetles from corn plants. (Rootworms are insects named for the worm-like appearance of their larvae.) Back at the lab, they raise the larvae for testing.

Using assays based on diet, seedlings and whole plants, they’re looking at how many larvae can survive on Bt corn. Besides looking for evidence of resistance, they hope to narrow down the assays to a single most useful test.

Referring to the larvae, she says, “so far we’ve seen no changes in susceptibility or ability to survive. That’s good news for growers, but we’re still worried based on what’s happening in the United States that this could become a problem here.”

Growers are still advised to rotate their crops from one season to the next. If they can’t do that, says Hitchon, then they should rotate types of Bt corn among three different Bt traits on the market.

Originally from Markham, Ont., she came to Guelph for an undergrad in wildlife biology. She intended to become an ornithologist. Still interested in birds, she found her interests shifting during her undergrad toward agriculture and ecology.

Hitchon completed her B.Sc. in environmental biology in 2012.

She discussed her research this semester as an entrant in Guelph’s Three-Minute Thesis competition for grad students. Having won the U of G contest, Hitchon competed at the provincials in April at McMaster University.