New use found for unregistered bio-fungicide

A bio-fungicide touted as a promising biocontrol of fusarium head blight in wheat, may ultimately be used for other purposes.

Field tests have shown that an un-registered bio-fungicide, called ACM941, can be used as a seed treatment to control root rot. It’s also effective against fusarium in corn.

Greenhouse tests show ACM941, a strain of the Clonostachys rosea fungus, controls fusarium head blight in wheat.

But field tests have been disappointing.

“When you take it outdoors, the activity has been quite inconsistent,” said Laurent Dumaine, chief executive officer of Adjuvants Plus, an Ontario company with the commercial rights to ACM941, a bio-fungicide developed by Agriculture Canada.

“Today, I would not consider it to be a commercially acceptable treatment for (FHB) in cereals.”

Dumaine, who grew up on a farm near Ile des Chenes, Man., and now lives in Toronto, said it’s been difficult to colonize the leaf tissue of wheat and other cereals with the bio-fungicide. That’s because field conditions can be hot, dry and windy, so the fungus struggles to get established. The physiology of wheat is also a factor.

When fusarium graminearum (the pathogen that causes FHB) infects wheat, it happens when the plant is moving from the vegetative to reproductive state. That’s a tricky time for the ACM941 fungus, as the leaf tissue on the plant is starting to die.

“It is a living organism. And for them to be effective they need to colonize the leaf tissue.”

The bio-fungicide is much more effective at establishing on corn and fighting off F. graminearum, which causes Gibberella ear rot.

It also has promise as seed treatment. Agriculture Canada research, done in the 2000s, showed its efficacy against the pathogens that cause root rot.

“We tested it for a couple years in the field… and we saw it was very good for seed treatment,” said Allen Xue, who discovered ACM941, in 1994, on a field pea plant in Manitoba.

It’s effective against Fusarium, Rhizoctonia and Pythium, the key pathogens that cause root rot.

“It will give you very good activity on three of those diseases and you get reasonably good activity on aphanomyces,” Dumaine said. “Aside from peas, you could use it as a seed treatment in wheat, oats, barley, lentils, corn, soybeans, and sunflowers.”

Besides seed treatments on multiple crops and foliar sprays on corn, there could be other uses for ACM941. It could be an effective foliar treatment for sclerotinia, a disease of canola and other crops, Dumaine said.

“That’s one (opportunity) I would rank ahead of (FHB) in cereals, in terms of our understanding of how the technology will perform.”

Another potential use could be something that’s an uncommon practice in Western Canada, or anywhere.

“You could also apply this product in the fall…. Apply it in the fall on trash (crop residue) in order to reduce disease levels,” Dumaine said. “The ability to reduce disease levels, from the fall to the spring, that could be a nice tool for growers…. That speaks to the point that this technology will have use in a whole bunch of different ways.”

Adjuvants Plus will apply for a pesticide registration with Health Canada this year. If things go to plan, the bio-fungicide will be registered by the fall of 2021.

By Robert Arnason