2.5 Chemical Elicitors

What Are Chemical Elicitors?

Chemical elicitors are substances applied to the tree to create controlled stress, telling the tree:

“You are under attack — activate defense.”

They do not create resin directly.
They trigger the tree to make resin by itself.

Purpose of Chemical Elicitors

Chemical elicitors are used to:

  • Strengthen the stress signal after wounding
  • Extend the tree’s defense response
  • Support resin formation when microbes are weak or absent

They are often used together with mechanical wounding.

Common Types of Chemical Elicitors (Conceptual)

A. Oxidative Stress Inducers

  • Create internal “alarm signals”
  • Increase defense chemical production

B. Mineral-Based Elicitors

  • Certain metal ions stress the tree at low levels
  • Common examples: manganeseiron

C. Acidic or Saline Stressors

  • Change pH or salt balance locally
  • Force defensive reaction

Dose is critical — too much kills the tree.

What Chemical Elicitors Actually Do Inside the Tree

  1. Enter through wound
  2. Cause controlled irritation
  3. Trigger oxidative stress
  4. Activate immune response
  5. Resin production begins

No immune response = no resin.

Benefits & Limits

Benefits

✔ Faster response than wounding alone
✔ More uniform resin zones
✔ Useful where microbes are unreliable

Limits

✘ Overuse causes toxicity
✘ Weak aroma if used alone
✘ Can lower quality if rushed

Farmer Key Message

“Chemicals wake the tree —
but only the tree makes resin.”

Best Practice for Farmers

✔ Use only approved / tested elicitors
✔ Follow exact dosage
✔ Combine with biological induction when possible
✔ Seal holes after application

Common Mistakes

✘ Using unknown or mixed chemicals
✘ Applying high concentration
✘ Repeating too often
✘ Expecting instant results

Chemical vs Biological Induction (Simple)

MethodSpeedQualityRisk
Mechanical onlySlowLowLow
Chemical elicitorsMediumMediumMedium
Biological (fungi)Slow–mediumHighLow–medium
Combined (best)BalancedHighControlled