True firs are more susceptible to these chemicles

Photo by Gary Chastagner, Washington State University.


Photo by Gary Chastagner, Washington State University.

  • 2,4-D and triclopyr are hormone-type herbicides used to control annual and perennial broadleaf weeds. These products are translocated throughout the plant.

Signs & Symptoms

  • Distorted plant parts, including twisting and curling on new growth
  • Swollen shoot tips
  • Severity of damage depends on amount applied, timing, and other herbicides in the mixture.
  • Damage also possible from drift of the herbicide

Where to Look

  • New growth is the most susceptible.

Similar Symptoms As

  • Shoot dieback

Management Options

  • Direct spray away from foliage. Use shields and low-drift nozzles.
  • If using a chemical, follow label directions for the rate, timing, and tree species.
  • Calibrate application equipment properly.
  • Avoid spraying on hot days. Amine forms are safer near trees.