Section 5. Native Forb Tolerance to Milestone® Herbicide

Milestone is a broadleaf herbicide that has reduced risk to the environment compared with other commercially available herbicides, making it a desirable alternative for invasive weed control on rangeland and wildland sites. Effect of Milestone on desirable native forbs is a consideration for land managers when making decisions about controlling invasive plants.

The following is a summary of experiments conducted at 16 locations in six states (Colorado, Idaho, Minnesota, Montana, North Dakota, and South Dakota) to determine long-term response of native forbs to Milestone applied in early summer (June) or fall (September or October), and to develop a tolerance/susceptibility ranking for native plants. Table 1 lists locations and researchers who conducted experiments.  

Results Summary

  • Most native forb species were moderately tolerant to tolerant, or recovered following treatment with Milestone® herbicide. 
  • Land managers can use these data as a guideline to evaluate risk and benefits to native plant communities when using Milestone for invasive species management. 
  • Milestone herbicide can be used to manage invasive plants in mixed plant communities and can serve as a catalyst to manage invasive plants and facilitate recovery of desirable forbs.

An electronic copy of the full report, Native Forb and Shrub Tolerance to Milestone Herbicide, can be accessed online at techlinenews.com.

 

Table 1. Descriptions of codes, locations, and researchers for 16 experiments conducted in six states.


Table 3. Tolerance rankings of forb species to Milestone® herbicide applied at either 5 or 7 fluid ounces per acre in summer and/or fall. Rankings are shown for 1 and 2 years after treatment (YAT). Forbs are listed alphabetically by common name within plant family (see Table 1 for location descriptions and Table 2 for category description). 

Table 2. Four categories for ranking tolerance of forbs and shrubs to Milestone herbicide


Figure 1. Comparison of tolerance rankings for 90 forb species 1 and 2 years after treatment, showing increase in tolerance by the second year following treatment with Milestone herbicide.