Rejuvra™, active ingredient indaziflam, has received approval by the Environmental Protection Agency (EPA) for use on rangeland, CRP land, and natural areas, including grazed areas on these sites. Indaziflam was previously marketed as Esplanade™; the new label for Esplanade™ will restrict its use to industrial vegetation management.
Rejuvra™ is a pre-emergent herbicide used for control of annual grasses like cheatgrass, Japanese brome, ventenata and medusahead. It reduces emergence of seedlings through inhibition of cellulose biosynthesis. For best results, it should be applied prior to seed germination, and it requires moisture (0.25-0.5” rainfall) within several weeks of application. Recommended application rate in areas grazed by livestock or cut for hay is 5 oz/A; in areas not grazed by livestock or cut for hay, recommended application rate is 5-7 oz/A. In a trial conducted in Gallatin County, MT, Rejuvra applied at 7 oz/A has provided 4 years of control of ventenata.
Research thus far has shown little to no injury to perennial vegetation growing in conjunction with annual grasses. The label lists perennial grasses, forbs, and shrubs that are tolerant to Rejuvra™. However, the label also states that if you are treating areas with desirable species not listed in the tables, treat a small area to confirm tolerance prior to large scale use. As a new active ingredient for controlling annual grasses, there is still more to learn.
If planting desired species into areas treated with Rejuvra™, avoid planting for at least 8 months and then conduct a field bioassay to determine residual herbicide effects on desirable species. The active ingredient persists, which is ideal for annual grass control, but needs to be taken into consideration if
revegetation is necessary as part of an integrated weed management plan. Rejuvra™ should be available in stores by mid-August.
Montana State University U.S. Department of Agriculture and Montana Counties Cooperating. MSU Extension is an equal opportunity/affirmative action provider of educational outreach.
