The Summer of Triclopyr: Growing Evidence of Off-Target Damage
This growing season, I have received many questions and concerns about triclopyr. Landscapers, nurseries, and property managers have reported several issues to the Purdue Plant and Pest Diagnostic Laboratory.
What is a Triclopyr?
What Triclopyr Controls
Triclopyr is used in various settings to control unwanted vegetation, including:
- Woody Plants: Trees like the tree of heaven and callery pears and shrubs like autumn olive and honeysuckle.
- Vines: Invasive species like kudzu and English ivy.
- Broadleaf Weeds: Herbaceous plants causing ecological or agricultural problems.
Where and When Triclopyr is Used
- Forestry: Clearing invasive species and managing forest regeneration.
- Agriculture: Controlling weeds and shrubs that interfere with crops.
- Aquatic Areas: Safe formulations manage invasive species near water.
- Rights-of-Way: Maintaining clear paths and preventing the spread of invasive plants.
Timing is crucial; triclopyr works best during the growing season when plants actively absorb nutrients and can transport the herbicide throughout their system.
Movement in the Plant
Triclopyr is absorbed through foliage and roots and moves throughout the plant. It travels upward through the xylem and downward through the phloem. This movement allows triclopyr to affect not just the treated areas but also parts of the plant not directly sprayed. This is effective for managing large plants through methods like hack and squirt treatments.
Phytotoxicity to Off-Target Plants
Volatilization Potential
Triclopyr is more volatile than some other herbicides, especially in its ester form. This can increase the risk of volatilization in certain environmental conditions, such as high temperatures and low humidity.
Off-Target Damage Due to Root Exudation
Root Exudation May Lead to:
Soil Contamination: Residual triclopyr in the soil can impact plant growth and health nearby.
Non-Target Plant Damage: Plants near treated areas might absorb triclopyr through their roots, leading to stunted growth or death.
Studies have shown that while triclopyr’s mobility in soil is low, it can still impact sensitive species. Damage might also occur through root grafting and/or mycorrhizae between plants, but research is still unclear.
Symptoms of Triclopyr Damage:
Symptoms of triclopyr damage are similar to other growth regulator herbicides. These symptoms can appear in small weeds in the sun within two hours but might take 48 hours or more for larger plants or shaded areas.
- Epinasty: Twisting, curling, and cupping of leaves and stems.
- Strapping: Leaves elongate and decrease in width, with significantly different margins.
- Water-Soaked Appearance: Darkened and wilted leaves.
- Necrosis: Blackening (death) of leaves, usually first seen in new growth.
- Spiraling Damage on Evergreens: Due to differences in vascular tissue, evergreens might show spiraling damage.
Trust Wells Lawn Care
Triclopyr is an effective tool for managing invasive and woody plants, especially large and stubborn species. However, careful management is needed to minimize risks to non-target plants and ecosystems. Understanding its plant movement, potential for volatilization, and impact through root exudation can help reduce unintended damage and maximize its benefits.
Let Wells Lawn Care help you manage those invasive and woody plants! Visit Wells Lawn Care Monthly Packages to learn more and get started today!