Key Plants and Key Diseases Indoors

Managing diseases in interior landscapes becomes more efficient when you know which plants are prone to specific pathogens. This guide identifies key indoor plants—those that frequently develop diseases—and their key diseases, based on common issues in interiorscapes.

Key Indoor Plants & Their Diseases

Aglaonema (Chinese Evergreen)

• Erwinia chrysanthemi (bacterial soft rot) – key disease
• Colletotrichum (anthracnose)
• Pythium (root rot)
• Pseudomonas cichorii (leaf spot)

Begonia

• Powdery mildew – key disease
• Impatiens necrotic spot virus (INSV) – key disease
• Botrytis (gray mold)
• Pythium (root rot)
• Foliar nematode

Brassaia / Schefflera

• Alternaria (leaf spot) – key disease
• Cercospora (leaf spot)
• Phytophthora (root rot)
• Virus

Chrysanthemum

• Pythium (root rot) – key disease
• Erwinia chrysanthemi (stem rot) – key disease
• Pseudomonas cichorii (leaf spot) – key disease
• Ascochyta, Alternaria, Stemphylium (leaf spots)
• Botrytis
• Powdery mildew

Cissus (Grape Ivy)

• Powdery mildew – key disease
• Downy mildew

Cyclamen

• Fusarium wilt – key disease
• Impatiens necrotic spot virus (INSV)

Dieffenbachia

• Erwinia chrysanthemi (soft rot) – key disease
• Phytophthora (root rot)
• Xanthomonas dieffenbachiae (leaf spot)
• Dasheen mosaic virus

Dracaena

• Colletotrichum (leaf spot) – key disease
• Fusarium (leaf spot/stem rot) – key disease
• Phyllosticta (leaf spot) – key disease

Epipremnum (Pothos)

• Pythium (root rot) – key disease
• Colletotrichum (leaf spot)
• Rhizoctonia (root rot)

Ficus

• Cercospora (leaf spot)
• Colletotrichum (anthracnose)
• Phomopsis (dieback)
• Glomerella (anthracnose)

Hedera (English Ivy)

• Colletotrichum (leaf spot) – key disease
• Xanthomonas hederae (bacterial leaf spot) – key disease

Peperomia

• Pythium (root rot) – key disease
• Cercospora (leaf spot)
• Phytophthora (root rot)

Syngonium

• Erwinia chrysanthemi (soft rot) – key disease
• Xanthomonas vitians (bacterial leaf spot) – key disease
• Cephalosporium (leaf spot)
• Rhizoctonia (root rot)

Philodendron

• Pythium (root rot) – key disease
• Phytophthora (root rot)
• Rhizoctonia (root rot)
• Erwinia chrysanthemi (soft rot)
• Xanthomonas dieffenbachiae (leaf spot)
• Pseudomonas cichorii (leaf spot)
• Dasheen mosaic virus

Schlumbergera (Holiday Cacti)

• Fusarium (stem rot) – key disease
• Impatiens necrotic spot virus (INSV) – key disease
• Pythium (root rot)

Saintpaulia (African Violet)

• Phytophthora (crown rot) – key disease
• Botrytis (gray mold)
• Powdery mildew
• Rhizoctonia (root rot)
• Erwinia chrysanthemi (soft rot)
• Foliar nematode

Management Strategies

• Monitor key plants weekly for early symptoms.
• Avoid overhead watering; keep foliage dry.
• Quarantine new plants 2–3 weeks.
• Use pasteurized media; sanitize tools.
• Remove infected leaves/plants promptly.
• Apply labeled fungicides/bactericides only when necessary.
• Optimize light, humidity, and air circulation for each species.

By focusing scouting efforts on these key plants and their key diseases, interiorscape managers can detect problems early and maintain healthier indoor plantings with less pesticide use.