Plant guide:ðĩ Cactus
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Fungal
Black Rot at the Base of Cactus
Commonly affects: Cactaceae (Cactus)
The very base of the cactus, where it meets the soil, turns black and soft, distinct from general basal rot in that it often progresses very rapidly.
Potential Causes
- 1Fungal or bacterial infection entering through the base, often in overly moist, poorly-draining soil
- 2Prolonged contact with wet soil or mulch at the base
- 3Wounds at the base from repotting or pest damage giving pathogens entry
Solution Steps
- 1Act quickly, since black rot at the base can progress and kill the plant within days
- 2Cut away all affected tissue immediately, checking that the cut surface shows clean, healthy tissue with no discolouration remaining
- 3If the rot has reached the plant's core, propagation from a healthy upper cutting may be the only way to save any part of the plant
- 4Repot survivors into fresh, fast-draining mix well away from the original contaminated soil
Prevention Tip
Fast-moving black rot at the base needs immediate action â don't wait to see if it resolves on its own, since it can consume the whole plant within days.
