Phoma Macrostoma Good to Go
The indigenous fungus (Phoma macrostoma) was granted full registration for the sale and use of Bio-Phoma technical Herbicide this past December by Health Canada.
Isolated from Canada thistle plants, it exhibits selective broadleaved weed control affecting weeds such as dandelion, clover, wild mustard, ragweed, and others. There are no effects on grassy weeds (green foxtail and wild oats) or crops, such as wheat, barley, oat, millet, kamut, and grasses.
image source: Agriculture and Agri-Food Canada
When applied before weed emergence, the fungus prevents weed establishment in turf for 1-3 months. Post-emergent applications result in susceptible plants turning white and subsequently dying. The fungus produces phytotoxins during its growth phase which are taken up by the susceptible plants. Weed control is obtained when a granular formulation of the fungus is applied to moderately moist soil when the air temperature is between 10–30°C. Trials have demonstrated up to 80–100% control of dandelion and wild mustard and 50-80% control of Canada thistle.
Phoma macrostoma has limited mobility in the soil because growth is primarily by mycelial fragments, thus staying mostly where placed. It is not very competitive with other soil mycoflora and its presence declines with time. One year after application, it is rarely detected in the soil and there are few carryover effects to non-target plants. Above 30°C, its growth is curtailed. Overall the fungus has minimal impact on the environment.
Agriculture and Agri-Food Canada has patents issued on this technology in 16 countries. In January 2017, the Horticulture and Agriculture Group of Premier Tech, an international leader in active ingredients for sustainable agriculture and horticulture, signed a license agreement with Agriculture and Agri-Food Canada (AAFC) to finalize the development and commercialization of an end-use product.