Field Identification
A white-rot basidiomycete complex that eats the lower trunk and roots of palms and hardwoods, often announcing itself with shelf conks at the soil line—by then substantial wood is already compromised. Palms often host Ganoderma zonatum; oaks and other hardwoods may carry related Ganoderma species.
Conks are woody, lacquered-looking brackets; internal decay shows as white spongy rot with dark zone lines. Palms may lean, drop fronds prematurely, or fail suddenly in wind because the structural cylinder is hollowed out.
How to Deal With It
Organic Control Methods
No curative spray exists; trunk-injected biologicals have mixed research—focus on cultural limits to spread. Phosphite-based products are synthetic-adjacent; stick to approved organic materials only if your certifier lists them.
Competitive fungi and compost teas are experimental supports at best; healthy soil food web may marginally slow colonization but will not resurrect dead cambium.
Avoid wounding trunks with string trimmers or mower hits; improve drainage; do not pile soil or mulch against root flares; remove and destroy infected stumps and roots to reduce inoculum—spores travel on equipment.
Cable bracing is a stopgap, not a cure; excavate and air-dry lower trunks only when arborists recommend to assess extent.
Sterilize chains between trees; plant resistant species in high-risk sites; never install palms on buried debris from old infested specimens.
Let Nature Handle It
Natural Enemies
- Competitive Saprophytic Fungi
- Soil Antagonistic Microbes
Threat Map