Ganoderma basal stem rot (coconut)
A lethal rot of the trunk base and roots with reddish-brown gum ooze and bracket fungi — the crown wilts and the palm dies.
- Pathogen
- Fungus (Ganoderma lucidum)
- Spreads by
- Soil & root contact; from stumps/roots
- Favoured by
- Stressed palms, poor drainage, water stress
- Main risk
- Trunk-base & root rot; crown wilts, palm dies
Overview
Ganoderma basal stem rot, also known as Thanjavur wilt or Ganoderma wilt, is a lethal soil-borne disease of coconut (and some other palms) caused by the fungus Ganoderma lucidum. It rots the roots and the base of the trunk (bole). A characteristic sign is the oozing of a reddish-brown gum/liquid from cracks at the base of the trunk, along with internal discoloration and rotting of the trunk base wood; later, the fungus’s bracket or shelf-shaped fruiting bodies appear on the trunk base.
As the roots and trunk base rot, the palm is cut off from water and nutrients: the outer/older leaves yellow, wilt and droop, the crown declines, nut yield falls, and the palm eventually dies. It is favoured by stressed palms, poor drainage and water stress, and it spreads through the soil and root contact, so it often appears in expanding patches. Because it is soil-borne and hard to reverse once advanced, management combines removing and destroying dead/severely-affected palms and their stumps/roots, isolation trenches, improving drainage and palm health, and root-zone treatment of early-affected and neighbouring palms.
How to identify it
- A reddish-brown gum/liquid oozing from cracks at the base of the trunk (bole).
- Internal discoloration and rotting of the trunk-base wood, and rotted roots.
- Bracket or shelf-shaped fungal fruiting bodies appearing on the trunk base later.
- Outer/older leaves yellowing, wilting and drooping, crown decline, falling yield and eventual death; often in expanding patches.
What causes it and when
- The soil-borne fungus Ganoderma lucidum, which rots the roots and trunk base.
- Spreads through the soil and by root contact, and from infected stumps and roots left in the ground.
- Favoured by stressed palms, poor drainage and water stress, and appears in expanding patches.
- Hard to reverse once advanced; the fungus persists in the soil on woody debris and roots.
Cultural & organic control
- Remove and destroy dead and severely-affected palms together with their stumps and as much root as possible.
- Dig isolation trenches around affected palms to stop root-contact spread to healthy palms.
- Improve drainage, avoid water stress, and keep palms healthy and vigorous with balanced nutrition and green manuring.
- Apply bio-agents (e.g. Trichoderma) to the root zone and avoid leaving infected woody debris/roots in the soil.
Chemical / root-zone treatment
- For early-affected and neighbouring palms, apply a recommended fungicide as a root-zone/root feeding treatment where advised.
- There is no reliable rescue for a palm with an advanced trunk-base rot — control is preventive and sanitation-based.
- Combine any treatment with drainage, palm health and removal of the source palms and their roots.
- Confirm the current root-zone treatment and integrated package for your area with your local KVK/coconut board.
Prevent it coming back
- Remove infected palms with their stumps/roots, use isolation trenches, and do not leave woody debris in the soil.
- Keep palms healthy and unstressed with good drainage, balanced nutrition and Trichoderma in the root zone.
- Treat early-affected and neighbouring palms and monitor the patch, following the integrated package.
Crops most at risk
Where this problem is called out in our crop guides — open a crop for the full package of practices.
Frequently asked questions
My coconut palm oozes reddish-brown gum from the trunk base and the crown is wilting. What is it?
Reddish-brown gum oozing from cracks at the base of the trunk, with a rotting trunk base and roots, wilting outer leaves and (later) bracket fungi on the bole, is Ganoderma basal stem rot (Thanjavur wilt). It is a lethal soil-borne disease. Remove and destroy the affected palm with its stump and roots, dig isolation trenches, improve drainage and palm health, treat neighbouring palms’ root zones, and don’t leave infected woody debris in the soil.
Why does Ganoderma wilt appear in expanding patches?
Because the fungus is soil-borne and spreads largely through the soil and by root contact between neighbouring palms, and it persists on infected stumps and roots left in the ground. So from one diseased palm it moves to the next along the roots, producing a patch that expands outward over time. That is why isolation trenches around affected palms (to break root contact), and removing infected palms with their stumps and roots, are central to stopping its spread.
Can a palm with advanced Ganoderma basal stem rot be saved?
Usually not — once the trunk base and roots are extensively rotted, the palm cannot be reliably rescued, and it is best removed and destroyed with its stump and roots to stop it acting as a source. The realistic aim is to protect the neighbouring and early-affected palms: isolation trenches, root-zone fungicide/bio-agent treatment, good drainage and palm health. Confirm the integrated management package with your KVK or coconut board.
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.