Ag Canada eyes bioherbicide use in crops

A bioherbicide that's expected to appeal to organic and conventional producers facing tough-to-kill, resistant weeds could soon be available.

Agriculture and Agri-Food Canada isolated and purified the indigenous fungus Phoma macrostoma that naturally infects dandelions, Canada thistle, clover and other broadleaf weeds without harming grasses and certain crops.

Agricultural applications

It’s currently only registered for controlling weeds in non-edible plants like turf grass, but the government department is eyeing expanding Phoma's application to include edible crops like wheat, barley and corn.

“I think we’re looking at three to five years,” says AAFC microbiologist Russell Hynes.

Canola and legumes are sensitive to Phoma, so the edible crops currently targeted are cereals and corn, he says. Additional research on its effects on soybeans still needs to be done.

AAFC also discovered there are no residue effects from Phoma’s application, meaning farmers could continue their traditional rotations, like following wheat with canola.

How it works

Phoma is absorbed into weed roots, causing the weeds to lose their ability to feed themselves, AAFC explains in its latest newsletter. The targeted plants turn white from lack of chlorophyll and then die.

If the fungus is applied prior to weeds appearing, they’ll emerge white and die before becoming established, AAFC says.

Benefits over traditional controls

Hynes says Phoma offers benefits over traditional, synthetic products when it comes to weed resistance.

Weeds won’t adapt as quickly as they would to synthetic controls as Phoma attacks weeds in several different ways, making it tougher for weeds to adjust.

“It could take a very, very long time; decades or even longer. It may not happen,” Hynes says.


Pest control product maker Premier Tech has teamed up with AAFC to commercialize Phoma, and Hynes indicates the firm can assist future regulatory steps.

Phoma should be available for the latter by next year, he says.

Bottom line

Phoma could help conventional farmers tackle problem weed patches.

Being more environmentally friendly has also attracted organic grower interest, adds Hynes. It’s all biodegradable, and basically blends back into the background microbial population that was always in the soil, he says.

Article by: Richard Kamchen