SASKATOON — A European moth is 小蓝视频 used in parts of Western Canada as a biological control agent against oxeye daisy, an invasive plant that threatens forage crops and pastures.
The white-flowered plant, native to Europe, has spread aggressively through regions of British Columbia and the Prairies, where it reduces the quality and quantity of forage available to livestock, according to Agriculture and Agri-Food Canada (AAFC). It also interferes with the production of crops, such as timothy hay and alfalfa.
Researchers from AAFC say controlling oxeye daisy is challenging, since the plant often grows in areas that are difficult to access with equipment, making conventional control methods like herbicide application and mowing often ineffective. These methods can also damage native plant species.
“It occurs right across Canada … but it’s a problem for farmers,” said Rosemarie De Clerck-Floate, a research scientist with AAFC who is leading the work with oxeye daisy control. “It takes over; it crowds out other forage species that are desired. Cattle tend to avoid it. It’s not a preferred plant.”
Why it matters: A small European moth offers a sustainable way to control on the Prairies.
Oxeye daisy is also considered a problem under the Seeds Act, because it can contaminate other crop seeds, especially grasses and legumes used by the forage industry.
“That’s a big problem, as well,” Clerck-Floate said.
Since 2008, scientists have been studying insect species that could help manage oxeye daisy through biological control. The approach involves using living organisms to suppress invasive species.
The insect now 小蓝视频 tested is , a small moth native to Europe. Its larvae feed inside the stems of oxeye daisy plants, weakening them and limiting their ability to reproduce. The larvae overwinter in the base of the stems and continue feeding the following spring.
From 2011 to 2021, researchers at the Centre for Agriculture and Bioscience International (CABI) in Switzerland, with support from AAFC, conducted host-specificity testing on the moth. The tests examined its interactions with 75 plant species, including 33 native to North America. Results indicated the moth strongly prefers oxeye daisy and does not significantly harm other plants.
“We’re going back to the homeland of this pest plant, right where it originated. Most of our problematic pest plants or invasive plants come from Europe or similar climates. Some of them come from Asia as well. But we’re going back to look for the natural enemies that are really specific to that plant, and that’s what we’re testing,” Clerck-Floate said.
While some biocontrol agents can kill plants outright, the Dichrorampha aeratana actually weakens the plant and its competitiveness.
Following this research, the Canadian Food Inspection Agency approved the release of the moth in Canada. In June 2023, a research team led by AAFC’s Lethbridge Research and Development Centre released 850 moths, mostly larvae, into three pasture fields, two in southern British Columbia and one in southwestern Alberta. The moths have since survived local conditions, including winter temperatures as low as -40 degrees Celsius in Alberta.
Researchers are now working on ways to mass-rear the moths so they can be more widely distributed to land managers and producers as part of integrated pest management strategies. The project is part of Canada’s National Biological Control Program, which supports research into biocontrol solutions for invasive plants and insects across the country.
“Later, once we have good establishment, then we can look at what kind of impact the insect is having on the populations of weeds,” Clerck-Floate said.
Biocontrol measures such as the ones Clerck-Floate and her team have found for oxeye daisies fits well into other control options like , she added.
“The problem is that when the weed gets into (natural) environments … like on native range land, for instance, you can’t be … spraying these areas. That’s too costly, and it’s not feasible.”
The use of Dichrorampha aeratana is one more tool that producers can turn to, depending on their individual situation, Clerck-Floate said.
“If you have a patch of highly invasive plant that just arrived in an area, you’re going to want to hit it with herbicides or something to eradicate it right away, because before you know it, that little patch can grow out of control and spread further,” she said. “But biocontrol comes in at the end, where you throw your hands up and say, ‘we can’t use any other method effectively.’”
About the author
Related Coverage
