Pothos Bacterial Infection: Leaf Spot, Soft Rot or Wilt?

A bacterial infection on pothos is worth taking seriously, but not every brown spot is one. Bacterial problems have a few tell-tale features: tissue that looks wet, turns soft, smells bad, or spreads fast. Confirm those before you cut or discard anything.

Three Ways Bacteria Show Up on Pothos

Bacterial leaf spot. University of Maryland Extension describes bacterial spots on indoor plants as black to brown, often watery lesions (UMD: bacterial leaf spots). They often sit between veins and look angular. They may have yellow margins, blister-like spots that run together, or centers that fall out. UC IPM adds that spots start as tiny water-soaked areas and turn dark gray or blackish as they enlarge (UC IPM: bacterial soft rots, leaf spots, blights, wilts).

Soft rot. UC IPM says soft rot bacteria turn tissue brown and mushy with an unpleasant odor. Stem tissue near the soil can brown and break down. On Dieffenbachia, a close relative in the arum family, UF/IFAS describes Erwinia soft rot as mushy, watery spots with a rotten, fishy smell (UF/IFAS PP286). It is worst in warm, humid conditions.

Bacterial wilt. UF/IFAS describes bacterial wilt of pothos, caused by Ralstonia solanacearum. Leaves wilt and the veins in leaves and stems turn black (UF/IFAS PP340: Pothos diseases). It is most severe in warm periods and spreads in irrigation water. Our pothos black stems guide covers this pattern in detail.

Rule Out the Look-Alikes

• Overwatering and root rot. Brown, soft tissue starting at the soil line, with dark, mushy roots, points to a root-zone problem first. See our pothos root rot guide.
• Edema. Brown patches on a plant whose mix stays saturated may be water injury rather than infection; see our pothos brown spots and edema guide.
• Sunburn and cold. Dry, bleached or scattered brown patches that appeared after a move, cold window or direct sun do not spread. See our pothos sunburn guide.

A bacterial spot usually looks wet at its edge and keeps enlarging. A physical injury stays the same size.

What to Do

1. Isolate the plant from other houseplants straight away.
2. Cut off spotted leaves at the petiole. UMD advises picking off and destroying individual spotted leaves. Bag them rather than leaving them in the pot.
3. Disinfect tools between cuts. UF/IFAS recommends surface disinfectants such as bleach on clippers and tools.
4. Remove soft stem sections back to firm, clean tissue. If the rot reaches the base, save what you can as cuttings.
5. Take cuttings only from clean stems. UC IPM advises using disease-free cuttings. Choose stems with no spots or soft tissue, and root them in fresh water or new mix in a clean container.
6. Keep the leaves dry. UC IPM advises against overwatering and overhead watering, and recommends dry foliage and good air circulation. UMD suggests watering early in the day so leaves dry quickly. Stop misting.
7. Discard a systemically infected plant. UMD says systemically infected plants cannot be cured and should be discarded. For bacterial wilt, UF/IFAS says there are no effective bactericides and recommends bagging and removing plants, soil and pots.

About Copper Sprays

UF/IFAS notes that copper compounds can slow the spread of Erwinia on Dieffenbachia but that no chemical treatment cures infected plants. NC State Extension lists copper products as preventive options in greenhouse production (NC State: bacterial leaf spot). On a single houseplant, removing infected tissue and drying the foliage matter more than any spray. If you use one, choose a product labeled for indoor ornamentals and follow the label.

Prevent It Spreading

NC State notes that leaf-spotting bacteria spread through splashing water and through handling plants while they are wet. They can also arrive on cuttings and young plants. Wash your hands after handling an infected pothos. Clean the pot and saucer with disinfectant before reuse. Inspect new plants and cuttings before they join your collection.

For general care, see the pothos hub.

References

• University of Maryland Extension: Bacterial Leaf Spots on Indoor Plants
• UC IPM: Bacterial Soft Rots, Leaf Spots, Blights, Wilts
• UF/IFAS Extension PP340: Pothos (Epipremnum aureum) Diseases: Identification and Control in Commercial Greenhouse Production
• UF/IFAS Extension PP286: Dieffenbachia Diseases: Identification and Control
• NC State Extension: Bacterial Leaf Spot on Greenhouse Ornamentals