The Real Christmas Tree Board

Herbicide tolerant and resistant weeds have changed weed control practices in most agronomic cropping systems and are now impacting Christmas tree producers. In this project, experiments were conducted to evaluate alternative control strategies, with an emphasis on multiple modes of action for herbicide resistance management.

The objectives of this study were to:

Objective 1. Survey growers to determine the prevalence of herbicide resistance and the most common modes of action for which resistance is a problem for Christmas tree growers. [notation: this objective was omitted from the final negotiated funded project, but PI Neal was able to accomplish this objective through a no-cost on-line survey.]
Objective 2. Identify safe doses and application timings (relative to tree phenology) for glyphosate-alternative herbicides (including FirstRate, Harmony, 2,4-D amine, and saflufenacil tank mixed with glyphosate).
Objective 3. Identify effective doses and application timings for control of glyphosate-tolerant weeds including horseweed (Conyza canadensis), lambsquarters (Chenopodium album), and ragweed (Ambrosia artemisiifolia). Research focused on glyphosate tolerant horseweed control options with preliminary research on the control of lambsquarters and ragweed.
Objective 4. Evaluate the safety of treatments from objective 3 on established white clover.
Objective 5. Evaluate use of a spray drone for postemergence herbicide applications in steep, uneven terrain.”