Quick-Reference Guide for Ethephon Application on Rubber Trees: Concentration Ratios and Operational Essentials

Formulation Specification	Dilution Ratio / Dosage per Tree	Active Ingredient Dosage	Application Scenario	Safe Application Interval
40% Ethephon Aqueous Solution	Diluted 5–10 times	1.5–3 liters of undiluted product per hectare	Applied to the tapping panel of mature, tapped rubber trees	Every 15–21 days
5% Ethephon Paste	1.2–1.6 grams per tree	0.06–0.08 grams of active ingredient per tree per application	Medium-to-low-yield rubber trees; trees with moderate vigor	Every 21–28 days
2% Ethephon Application Agent	Applied directly	0.02–0.04 grams of active ingredient per tree per application	Rubber-growing regions in Yunnan; young rubber trees that have recently begun tapping	Every 21 days or longer
Low-concentration 0.5% Ethephon Solution	Applied directly	Low-dosage stimulation	Sensitive varieties; rubber trees with weaker vigor	Every 30 days or longer

Key Operational Guidelines
When preparing the solution, mix thoroughly with clean water according to the specified ratio.
Prepare only what is needed for immediate use; do not store the solution for long periods, as it will lose its efficacy.
For the first application, start with the lowest recommended concentration. Observe the latex flow over 3–5 tapping sessions;
only adjust the dosage if no abnormalities are detected.
The increase in yield is most pronounced during the first tapping session after application. A slight decline in dry rubber content may occur during the second to fourth sessions, followed by a stabilization from the fifth session onward—this is a normal physiological response.

Strictly avoid excessive application. Exceeding 0.08 grams of the active ingredient per tree per application can disrupt latex flow along the tapping cut. Long-term over-application can lead to "dry bark" (bark necrosis), causing the tree to stop producing latex.

Core Precautions for Ethephon Application on Rubber Trees
Tree Suitability and Restrictions
Prohibited Trees:
Never apply ethephon to young trees, trees that have not yet been tapped, or weak/diseased trees. Doing so will cause premature aging and prevent the trees from being tapped for latex production in the future.

Strict Control of Dosage and Frequency:
Excessive or frequent application damages the biological membranes of the tree, severely weakening its natural resistance. This ultimately leads to "dry bark" (bark necrosis) and irreversible losses in latex yield.

Supplementary Fertilizer and Water:
Following application, it is essential to enhance water and fertilizer management. This replenishes the significant amount of nutrients consumed by the tree due to the stimulated latex production, preventing a rapid decline in the tree's overall health.