Initial efficacy of Indazaflam on cheatgrass rangelands

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

Submitted to: Society for Range Management Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/4/2019
Publication Date: 2/16/2020
Citation: Clements, D.D., Harmon, D.N., Quicke, H. 2020. Initial efficacy of Indazaflam on cheatgrass rangelands. Society for Range Management Meeting Abstracts. 73:63. February 16-20, 2020 Denver, CO.

Interpretive Summary: The accidental introduction and subsequent invasion of cheatgrass (Bromus tectorum) throughout millions of hectares of Intermountain West rangelands has resulted in astronomical changes to many plant communities. 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 cheatgrass-infested rangelands to improve restoration/rehabilitation efforts. The use of pre-emergent herbicides have proven to be very effective in decreasing cheatgrass densities and seed banks which are limiting to the establishment of perennial species through competition for limited resources. Inazaflam, 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 Indazaflam on cheatgrass control in northern Nevada compared to other pre-emergent herbicides that we have experienced good cheatgrass control with, Imazapic and Sulfometuron methyl. 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. Indazaflam plots reduced cheatgrass initial densities by 94.8%, while Sulfometuron methyl experienced 99.9% followed by 97.8% for Imazapic. When attempting cheatgrass control efforts it is important to understand that control must nearly reach 100% due to the prolific ability of cheatgrass to produce seed and build persistent seed banks. As few as 43 cheatgrass seedlings/m² can outcompete perennial grasses at the seedling stage. The reported residual ability of Indazaflam for up to 4-years may add longer-term control of cheatgrass that could benefit residual and seeded perennial species.

Technical Abstract: The accidental introduction and subsequent invasion of cheatgrass (Bromus tectorum) throughout millions of hectares of Intermountain West rangelands has resulted in astronomical changes to many plant communities. 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 cheatgrass-infested rangelands to improve restoration/rehabilitation efforts. The use of pre-emergent herbicides have proven to be very effective in decreasing cheatgrass densities and seed banks which are limiting to the establishment of perennial species through competition for limited resources. Indaziflam, 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 cheatgrass control in northern Nevada compared to other pre-emergent herbicides that have experienced sufficient cheatgrass control such as Imazapic and Sulfometuron methyl Chlorosulfuron. Due to the environments of the cold desert of Nevada rangelands, we applly 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 cheatgrass initial densities by 94.8%, while Sulfometuron methyl Chlorosulfuron experienced 99.9% followed by 97.8% for Imazapic. Indaziflam treated plots however experienced significantly lower seed bank densities 1-year following application. When attempting cheatgrass control efforts it is important to understand that control must nearly reach 100% due to the prolific ability of cheatgrass to produce seed and build persistent seed banks. As few as 43 cheatgrass seedlings/m² can out compete perennial grasses at the seedling stage. The reported residual ability of Indaziflam for up to 4-years and significant reductions in cheatgrass seed banks may add longer-term control of cheatgrass that could benefit residual and seeded perennial species.