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Brown Spots (Extrafloral Nectaries) on philodendron

philodendron with brown spots (extrafloral nectaries)

What's Happening

Philodendrons produce sugary sap from glands called extrafloral nectaries (EFNs) to attract ants for protection. Indoors, without ants to clean the sap, it dries and causes localized chemical burns on leaf undersides, appearing as small brown or translucent spots. This is a physiological response to stress, not an infection.

How to Fix It

  1. 1

    Gently wipe leaf undersides weekly with a damp microfiber cloth to remove sap before it burns the tissue.

  2. 2

    Assess for environmental stress: low humidity (<50%) and inconsistent lighting can trigger excessive sap production.

  3. 3

    Do not treat with fungicides as these spots are not pathogenic.

How to Prevent It

Maintain stable high humidity (60-80%) and bright indirect light. Incorporate underside wiping into your weekly maintenance routine, especially for varieties like 'Ring of Fire', 'Birkin', and 'Congo Rojo'.

Related Problems

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Frequently Asked Questions

What causes brown spots (extrafloral nectaries) on my plant?
Philodendrons produce sugary sap from glands called extrafloral nectaries (EFNs) to attract ants for protection. Indoors, without ants to clean the sap, it dries and causes localized chemical burns on...
How do I fix brown spots (extrafloral nectaries)?
Gently wipe leaf undersides weekly with a damp microfiber cloth to remove sap before it burns the tissue.. Assess for environmental stress: low humidity (<50%) and inconsistent lighting can trigger excessive sap production..
How do I prevent brown spots (extrafloral nectaries) from happening again?
Maintain stable high humidity (60-80%) and bright indirect light. Incorporate underside wiping into your weekly maintenance routine, especially for varieties like 'Ring of Fire', 'Birkin', and 'Congo ...