A fungus, imported from Columbia, is being introduced as a bio-control agent for one of the country's most challenging weeds.

Flaxleaf fleabane is a prolific seed producer and can cause grain crop revenue losses of more than $43 million each year.

Rural editor Sophie Clarke caught up with CSIRO weed ecologist Doctor Ben Gooden who says introducing the fungus will help reduce overall populations without hurting other non-targeted species.