Efficacy of indaziflam on downy brome control in northern Nevada

Authors: Clements, Darin - Charlie; Harmon, Daniel - Dan; QUICKE, HARRY - Bayer Corporation

Submitted to: Western Society of Weed Science
Publication Type: Abstract Only
Publication Acceptance Date: 1/19/2020
Publication Date: 3/3/2020
Citation: Clements, D.D., Harmon, D.N., Quicke, H. 2020. Efficacy of indaziflam on downy brome control in northern Nevada. Western Society of Weed Science. 20:224.

Interpretive Summary:

Technical Abstract: The accidental introduction and subsequent invasion of downy brome (Bromus tectorum) throughout millions of hectares of Intermountain West rangelands has resulted in astronomical changes to many plant communities. Downy brome, also known As cheatgrass, is native to the cold deserts of central Asia where humans are first thought to have domesticated animals. These native habitats are very similar to the big sagebrush (Artemisia tridentata)/bunchgrass and salt desert ranges of the Intermountain Area of North America. Resource managers need tools to conduct aggressive and effective weed control practices on downy brome-infested rangelands to improve restoration/rehabilitation efforts. The use of pre-emergent herbicides have proven to be very effective in decreasing downy brome densities and seed banks which are limiting to the establishment of perennial species through competition for limited resources. Inaziflam, Esplanade, is a pre-emergent herbicide recently available for research on Nevada rangelands. In 2018 we started a research project to measure the efficacy of Indaziflam on downy brome control in northern Nevada compared to other pre-emergent herbicides that we have experienced good downy brome control with, Imazapic and Sulfometuron methyl Chlorosulfuron. Due to the environments of the cold desert of Nevada rangelands, we applied these pre-emergent herbicides in the fall of the year, fallow the site for 1-year and then seed with desirable perennial species. Indaziflam plots reduced downy brome initial densities by 94.8%, while Sulfometuron methyl Chlorosulfuron experienced 99.9% followed by 97.8% for Imazapic. When attempting downy brome control efforts it is important to understand that control must nearly reach 100% due to the prolific ability of downy brome to produce seed and build persistent seed banks. As few as 43 downy brome seedlings/m² can out compete perennial grasses at the seedling stage. The reported residual ability of Indaziflam for up to 4-years may add longer-term control of downy brome that could benefit residual and seeded perennial species.