Beetle-resistant potato varieties

The Colorado potato beetle is considered a major economic pest of potato. Photo: John Morrison, AAFC

New potato varieties that are naturally resistant to Colorado potato beetle could be on the market in five years, according to Helen Tai, a potato breeder at Agriculture and Agri-Food Canada’s Potato Research Centre in Fredericton.

Tai is the lead on the breeding project, which has been underway for 30 years, she says, since AAFC breeder Henry de Jong brought wild potato relatives to Canada from their native South America.

Those species were tested in Canadian fields for their resistance to potato beetles and nine were identified that had some natural resistance. Crosses from these nine species also showed resistance.

Tai’s program uses natural sources of resistance in crosses and does not produce genetically modified organisms. When she came on board the breeding project several years ago, the team began assessing chemical differences between resistant and non-resistant plants.

“What some of the wild species are doing is producing a chemical, an anti-feedant that the beetle doesn’t like,” she explains. “It doesn’t actually kill the beetle — it just deters the beetle.”

The team is currently developing a DNA marker based on the resistant plants’ chemical profile and can use marker-assisted selection to look at large numbers of progeny from their crosses to see which ones have resistance, she says.

Two varieties are already ready for accelerated release. Companies can submit cash bids for sole rights to trial these selections. The winning company continues field trials for the varieties and can license the variety for commercialization. Winning bids will be published online in March.

AAFC will retain rights to continue working with the breeding material, says Tai, along with other sources of resistance.

If a company puts in a bid this year, the new varieties could be ready for farmers’ fields in five years.

A natural option

It’s good timing for a natural alternative to chemical controls of potato beetles.

The pest is considered a major economic pest of potato. It’s currently controlled Canada-wide by imidacloprid, a neonicotinoid insecticide, but the future of imidacloprid is by no means certain in Canada.

Health Canada’s Pest Management Regulatory Agency is currently completing an environmental risk assessment of imidacloprid. In 2017, PMRA proposed a three- to five-year phase-out of the insecticide for agricultural use, based on assessments that found negative impacts on waterways. A final decision on whether imidacloprid will be deregistered for agricultural use is expected by late 2018.

But that’s not the only reason alternative controls are needed. Tai says researchers have documented resistance to imidacloprid.

Plus, chemical controls are costly for growers, and there are market segments, such as organic producers, home gardeners and hobby farmers, where potatoes with natural resistance are highly desirable.

“There are concerns, there are questions,” she says. “There are a lot of reasons to move toward resistant varieties.”

Tai says potato growers should let seed suppliers know if they’re interested in these new varieties. “It takes some time for the production system to respond but we need to get the information out there. Interest in it will help us to provide the materials,” she says.