(atrazine, simazine, Velpar and others)
Douglas-fir and newly planted seedlings are more sensitive to damage

Photo by RIcky Bates, Penn State University.


  • Triazines are herbicides used to control grasses and some broadleaf weeds. These products are photosynthetic inhibitors.

Signs & Symptoms

  • Yellowing on needle tip and margin
  • More pronounced damage with higher temperatures
  • Light-textured soils prone to more damage

Where to Look

  • Newly planted container seedlings or sites with light-textured soils.

Similar Symptoms As

  • Current season needle necrosis

Management Options

  • Know spray timing and product options and usage. This information is critical.
  • Carefully read all label instructions and precautions prior to purchasing and applying these herbicides.
  • Apply lower product rates on light-textured soil.