Common Houseplant Diseases

Dr. John F. Baniecki
WVU Extension Service
Plant Pathology and Entomology Specialist
August 2000

Close observation, sound interpretation and prompt remedial action are those activities that belong to the TLC (Tender Loving Care) method of successfully maintaining beautiful house plants. Remember, not all problems are caused by improper care; that is too much, insufficient, or improper water, light, temperature, fertilizer, or soil conditions.

Animals can usually do something to better their environment; most can at least move and seek more favorable spots. A plant must sit and take it. Only you can promote its welfare. If you fail to do that effectively, you are likely to be your plant worst enemy.

Diseases	Description	Favored by
Powdery Mildew	White powdery coating on leaves, buds and stems	Too much humidity associated with poor air circulation.
Root-Stem-Crown Rot	Fungal caused. Roots rotten and decay. Stems and crowns watersoaked and darkened at soil level. Stems collapse or wilt and die.	Poor drainage or overwetness and excessive soil compaction.
Damping-off	Fungal caused. Seedlings turned dark at the soil level, eventually rot and fall over.	Non-pasteurized or non-sterilized soil.
Gray Mold or Botrytis Blight	Fungal caused. A whiskery fuzz of gray mold covers young foliage, flower buds or flowers, usually causing them to become damp and decay.	Too much humidity or watering and poor circulation.
Nematode	Worms, microscopic in size. Small swellings on roots. Plants may be stunted and sickly.
Virus	Plants dwarfed with crinkled or cupped leaves; leaves may be mottled light and dark green between the veins.	Insects-(aphids, for example) may serve as carriers of the virus.
Leaf Scorch	Leaves yellowish, scorched at margins and tips and may wilt.	Locations in the direct sun.
Leaf Drop	Leaves turn yellow or brown, may wither and drop.	Too high room temperature. Dry or excessive moisture in the atmosphere. Inadequate lighting. Pot bound condition (needs repotting). Pollutant may be the air. Location in direct sun (sun injury). - or simple old age or natural dying.
Chlorosis	Leaves turn yellow, but veins remain green.	Inability of plants to obtain sufficient iron.
Dropsy or Edema	Watersoaked spots on leaves, later turning corky; corky ridges on leaf stems.	Excessive moisture (provide better light and ventilation).