Ganoderma Butt Rot in Palms: Identification, Spread, and Management

Understanding the Disease

Ganoderma zonatum is a lethal fungal pathogen that causes butt rot in palms. It produces shelf-like conks (fruiting bodies) at the base of the trunk. There is no cure; infected palms decline slowly over 3–4 years.

Case Summary

A foxtail palm (Wodyetia bifurcata) planted too deep developed root rot, then Ganoderma conks appeared. Copper fungicide shriveled conks but didn't stop internal decay. Nearby Christmas palms (Adonidia merrillii) now show conks 50 feet away, indicating soil-borne spore spread.

Recommended Actions

1. Remove infected palms immediately. Do not wait for total decline.
2. Excavate soil 3 feet in all directions and 3 feet deep around the stump; replace with clean fill.
3. Do not replant palms in the same spot. Choose non-host plants (e.g., ornamental grasses, shrubs).
4. Monitor neighboring palms for conks; remove any that appear.
5. Sanitize tools with 10% bleach between cuts.

Planting New Royals

Royal palms (Roystonea regia) should be planted at least 50 feet from known infection sites. Spores persist in soil for years; no fungicide prevents infection.

Early removal and soil replacement are the only ways to protect your landscape.