Comparing the efficacy of organic and conventional herbicides for the control of invasive plant species

Principal Investigator: Valerie Eviner

Many governmental and non-governmental entities that manage invasive plant species in wild land settings are being pressured by a range of interest groups to stop using all conventional herbicides.

While integrative pest management approaches such as controlled burns and controlled grazing are sometimes promising, they vary in their effectiveness and can be difficult or impossible to implement with the precise timing required.

There is substantial interest in the use organic herbicides to fill the void left by the loss of conventional herbicides but scientific studies describing methods for the effective use of organic herbicides in wild land settings are almost non-existent.

Because the mode of action of organic herbicides is so different, organic herbicide studies need to focus, not simply on determining the extent to which organic herbicides can replace conventional herbicides, but also on developing new best practices tailored to the unique characteristics of organic herbicides.

In these trials we will assess to what extent organic herbicides can be used to control exotic annual grasses (e.g. clearing the way for restoration, or recovery of wildflowers), and to what extent organic herbicides may be used to selectively kill noxious annual grasses, medusahead and goatgrass, from a matrix of more beneficial annual grasses (e.g. wild oats, bromes).