Pink Disease in Rubber

Erythricium salmonicolor on the branch fork or upper trunk: how the pink cottony growth girdles branches and how to prune, treat, and prevent.

Pink disease (Erythricium salmonicolor, syn. Corticium salmonicolor) attacks the branch forks and upper trunk of rubber. It forms a distinctive pink-salmon cottony growth on the bark, girdles the branch, and causes canopy dieback above the infection point. Most common in wet upland and highland blocks, and on younger stands where branch bark is still tender.

Cause

• High humidity and prolonged wet weather (> 200 mm/month)
• Dense canopy with poor airflow
• Young smooth bark on branches (year 3 to 10 stands)
• Susceptible clones vary by region
• Wounds at branch forks (e.g. from wind damage)

Effect

Stage	Symptom
Early	White cobweb-like mycelium on the underside of a branch or at the fork
Mid	Pink-salmon cottony growth becomes visible on the branch
Late	Bark cracks, branch girdles, canopy above the infection dies back
Terminal	Branch dies, may progress to whole-tree canopy loss on severe cases

Satellite signals

Index	What to watch	Threshold
NDVI	Scattered small canopy gaps in mid-age stands	Direct high-res observation

Satellite rarely resolves individual pink-disease events. Ground scouting is the main detection method.

Action

1. Confirm at the branch fork

   Pink or salmon cottony growth on the branch or at the fork confirms pink disease. Common target: branch forks 2 to 4 m above the ground on year 3 to 10 trees.

2. Prune and burn

   Cut the infected branch 30 cm below the visible infection. Burn removed material on site (do not compost or leave in the block).

3. Apply wound protectant

   Paint the cut end and the surrounding bark with Bordeaux paste or copper oxychloride paste. Repeat every 2 weeks for 6 weeks.

4. Systemic fungicide on early cases

   On early cases where the branch is still worth saving, spray or paint with tridemorph or carbendazim every 10 days for 4 rounds.

5. Improve canopy airflow

   On chronic blocks, discuss selective pruning or thinning with plantation manager to improve airflow and reduce humidity.

Recommended alert settings

Trigger	Condition	Severity
Scout report	Any pink-cottony growth on branch or fork	High
Cluster	> 3 trees in a block within 1 month	Critical (block-wide prophylactic spray)
Wet-weather advisory	> 200 mm/month sustained on year 3-10 blocks	Medium

Related

• Black stripe
• Field Walk Protocol
• Rubber Diagnosis