Pink disease
A pinkish-white fungal crust on the fork and branches of rubber in prolonged wet weather, girdling the branch and causing dieback beyond it.
- Pathogen
- Fungus (Corticium salmonicolor)
- Spreads by
- Spores in wet, humid weather; enters at branch forks
- Favoured by
- High rainfall, dense humid shaded canopy
- Main risk
- Branch girdling and dieback; loss of the tree top
Overview
Pink disease is caused by the fungus Corticium salmonicolor (also called Erythricium salmonicolor). It attacks the bark of the fork and the main branches of rubber, usually entering at the branch fork. In prolonged wet, humid weather a pinkish-white fungal encrustation spreads over the bark, which cracks and bleeds latex ("gumming") down the trunk. The fungus girdles the bark, so the branch beyond the infection dies back.
It is worst in high-rainfall pockets and in dense, humid, poorly lit canopies where the bark stays wet. Left alone, it can kill a major branch or the top of a young tree. Management is early detection and surgery — cutting out the affected wood well below the infection and painting the wound with a recommended fungicide — combined with keeping the canopy open enough to dry.
How to identify it
- A pinkish-white, later whitish, fungal encrustation on the bark of the fork and main branches.
- Cracking bark and latex bleeding down the trunk from the infected zone (gumming).
- Dieback of the branch or shoot beyond the infection — leaves wilt, brown and hang.
- Worst in the monsoon, in high-rainfall pockets and in a dense, shaded, humid canopy.
What causes it and when
- The fungus Corticium salmonicolor, spreading in prolonged wet, humid weather, usually entering the tree at the branch fork.
- Active mainly through and after the monsoon; favoured by a canopy that stays wet because it is dense and poorly ventilated.
- Young trees building their frame are especially vulnerable to losing a major branch or the top.
Cultural control
- Inspect the forks and main branches during and after the monsoon so lesions are caught early.
- Prune and regulate shade so the canopy is not a dense, humid, poorly lit trap.
- Improve drainage so the wettest parts of the plot do not stay saturated.
Treatment
- Cut out and destroy the affected branch or bark well below the visible infection at the first sign.
- Paint the cut surface and the fork with a recommended fungicide (Bordeaux paste or a systemic fungicide), and repeat after rain.
- Treat early lesions before the branch is girdled — once dieback is obvious, the branch or top is usually lost.
- Confirm the current product and method for your area with the Rubber Board or your local RRII office.
Crops most at risk
Where this problem is called out in our crop guides — open a crop for the full package of practices.
Varieties to consider
Named seed varieties whose resistance or susceptibility to this problem is documented on their own variety page.
Frequently asked questions
There is a pink crust on the fork of my rubber trees. What should I do?
That is pink disease, a bark fungus that spreads in wet weather and girdles the branch. Act early: cut out the affected wood well below the crust and destroy it, then paint the wound and the fork with a recommended fungicide such as Bordeaux paste, repeating after rain. Also open up the canopy where it is dense and humid. If the branch is already dying back beyond the infection, it is usually too late to save that branch.
Why does pink disease keep coming back in the same block?
It thrives where the bark stays wet — high-rainfall pockets and dense, shaded, poorly ventilated canopies. If the canopy and shade are not opened up and the drainage is not improved, the conditions that favour the fungus persist and new infections appear at the forks each monsoon. Regulating the canopy is as important as treating the lesions.
Symptoms and control measures follow ICAR, KVK and state agricultural-university package-of-practices; any named chemical is a registered use. Always read the product label and confirm the dose for your crop and zone. editorial policy.