A fungus that makes thistles and dandelions sick is making Saskatoon scientist Karen Bailey smile.
She and her associates at Agriculture Canada have announced that they have turned two decades of collecting ill thistles into a bioherbicide.
Phoma macrostoma is a fungus that interferes with some broadleaf weeds’ abilities to use chlorophyll. Most affected are dandelion, Canada thistle and white clover, all costly weeds to prairie agriculture.
Bailey said the work started with thistles gathered at the federal research centre in Regina in 1985 and spread across the country to the Maritimes and eastern Canada.
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She said the soil-applied fungus is most effective on the weeds’ root systems.
“We’ve tried (testing) traditional sprayed applications, but this likely going to be most effective (in a granular form) where it comes into contact with the roots,” she said.
Scotts Co., the Ohio-based lawn care products giant and maker of popular brands such as Scotts, Miracle-Gro, Ortho, Osmocote, Hyponex and Earthgro as well as consumer retailer of Monsanto’s Roundup, is working with Ag Canada to develop a system of commercial production for the granular herbicide.
Scotts will also share some of the costs of development and regulatory approvals that will be required to get the fungus into the hands of consumers, turf grass producers and golf course operators.
“Initially I thought it would be 2009 when the product reached the market, but I just met with Scotts and they feel we can do it by 2007,” said Bailey.
“There will be a lot of expensive steps left before we can commercialize the product and we plan to learn from the relationship with Scotts and build on that when we select a partner to develop and market the agricultural application,” she said.
Both dandelion and Canada thistle populations have increased under the lower tillage production techniques that have been adopted by grain producers in the past 15 years.
Control of these weeds has been difficult due to their resistance to both drought and chemicals and their seed systems that spread by wind.
“The fungus doesn’t affect monocots such as corn and other cereals and … a year after it is applied, it is virtually gone from the soil,” Bailey said.
“We’ve planted field peas a year after applying the (bioherbicide) and it had no effect.”
Like any fungus, the Phoma macrostoma thrives in moisture, but Bailey said this one is tough in drought conditions.
“When the Canada thistle starts to wilt, that is when the fungus stops working, and that is pretty dry.”
The fungus also competes poorly with other soil organisms so it appears to have limited effect on non-target flora and fauna.
Phoma macrostoma is most effective on newly emerged weeds, so it will likely require early spring application but will likely have some in-season residual properties.
Testing for toxicity on birds, fish and animals is now beginning and, after two more years of research, Bailey hopes to be able to apply for registration of the product.
