Diseases and Parasites of Indoor Caladium: Identify and Protect Your Plant

Common Diseases and Problems of Caladium

Caladium is a robust plant, but certain cultivation mistakes or unfavourable conditions can affect its development. Here are the main common diseases and abnormalities along with solutions to remedy them.

Tuber rot

This manifests as a tuber that becomes soft, blackish and emits an unpleasant odour. A plant affected by this issue may never grow or wither quickly after planting.

This phenomenon is caused by excessive moisture in the substrate, insufficient drainage and/or overly frequent watering. Temperatures that are too cool at planting time can also prevent the tuber from sprouting properly, encouraging rot.

Solutions:

• Check that the tuber is firm and free of soft spots before planting.
• Use a well-draining substrate, enriched with perlite, and a pot with drainage holes.
• Water moderately and allow the soil to dry slightly on the surface between waterings.
• Plant tubers only when temperatures are above 20°C.

→ Consider placing your pots in a mini greenhouse: the temperature will be higher, ambient humidity too, and watering needs—and thus watering mistakes—will be reduced.

Small leaves and pale colours

A Caladium with small, pale leaves often lacks light or essential nutrients, indicating insufficient fertilisation or poor substrate.

Solutions:

• Place the plant in a very bright spot, near a window, but without direct sunlight which could scorch its foliage.
• Fertilise every 4 to 6 weeks with a phosphorus-rich fertiliser during the growth period.
• Use a high-quality potting mix, rich in organic matter to promote healthy development.

Weak or non-existent growth

If the Caladium isn’t growing or is growing very slowly, this often indicates suboptimal conditions. Low temperatures slow its development, and a lack of nutrients can limit new leaf production.

Solutions:

• Maintain a stable temperature around 20-25°C, especially in spring and summer.
• Ensure fertilisation is regular and suited to the plant’s needs.

Curled leaves

When Caladium leaves start curling inward, this often indicates overly dry air or temperature-related stress. This issue is common indoors, particularly during heating periods. Caladium thrives in 50-70% humidity.

Solutions:

• Increase ambient humidity by placing a humidifier nearby.
• Or mist the leaves regularly with non-calcareous water, avoiding excess to prevent fungal diseases.
• Maintain a stable temperature, free from drafts, above 18°C, ideally above 20°C.

→ Note: Some thin-leaved, sensitive cultivars dislike misting, which can cause other issues depending on water quality or lead to foliar spotting. A humidifier is ideal.

Leaf spots

Brown or black spots on Caladium leaves can be caused by fungi linked to excess moisture or poor air circulation. If untreated, these spots can spread and cause gradual leaf desiccation.

Solutions:

• Remove affected leaves to limit spread.
• Avoid overhead watering; keep leaves dry during watering.
• Place the plant in a well-ventilated area to improve air circulation.

Powdery mildew

Powdery mildew is recognisable by a white, powdery coating on leaves. It appears in humid, stagnant conditions with poor air circulation.

Solutions:

• Remove affected leaves.
• Apply a sulphur-based treatment, or baking soda, or milk.

Read our guide to learn about treatments for powdery mildew.

Other common issues

Certain abnormalities are also frequent in Caladium and can be corrected with simple adjustments:

• Yellow leaves: often caused by overwatering or the onset of dormancy in autumn (in which case, it’s entirely normal). Adjust watering and check substrate drainage.
• Soft leaves: indicate either underwatering or excess moisture weakening the roots. Check substrate drainage and adjust watering.
• Brown leaf edges: signs of overly dry air or mineral salt buildup from tap water. Increase ambient humidity and use non-calcareous water.

Caladium leaves are delicate and can be quite sensitive

Main Pests of Caladium

Caladium, with its tender and colourful foliage, can be targeted by several parasitic pests that weaken the plant and spoil its appearance. These pests generally thrive under specific conditions, such as overly dry air or excessive moisture. Regular monitoring helps identify infestations quickly and take action before they become problematic.

Red Spider Mites

Red spider mites, or tetranychids, are microscopic mites that proliferate particularly in dry and warm air. They attack the foliage by sucking the sap, causing leaves to yellow and appear discoloured. Fine webs may also be visible under the leaves in advanced infestations.

Solutions:

• Rinse the plant with water.
• Increase ambient humidity by misting the plant or using a humidifier.
• Clean the leaves regularly with a damp cloth to remove mites.
• For severe infestations, apply a natural acaricide based on black soap or introduce beneficial insects.

→ Discover our treatment tips in our article on red spider mites.

Aphids

Aphids are small insects that cluster on young shoots and under leaves. They feed on sap, causing leaves to curl and growth to slow. Their presence is often accompanied by a sticky residue called honeydew, which can encourage sooty mould.

Solutions:

• Rinse the plant with water.
• Spray leaves with water mixed with black soap to eliminate them.

→ Read our guide to learn all about aphids.

Mealybugs

Mealybugs appear as small white, cottony clusters on stems and under leaves. They weaken the plant by sucking its sap, leading to yellowing and general foliage decline.

Solutions:

• Remove mealybugs manually with a cotton swab dipped in 70% alcohol.
• Apply a treatment of black soap diluted in water, mixed with alcohol and rapeseed oil.
• Check the plant regularly and isolate infested specimens to prevent spread.

→ Read our article on treating mealybug infestations.

Fungus Gnats

Fungus gnats, often called soil flies, are small black insects that hover around the potting mix. The real issue lies in their larvae, which feed on roots and weaken the plant, especially when young.

Fungus gnats thrive when the potting mix remains constantly moist.

Solutions:

• Allow the potting mix to dry slightly between waterings to prevent larvae development.
• Place yellow sticky traps to catch adult flies.
• Cover the potting mix with clay pebbles or small stones.
• For severe infestations, use an organic treatment with nematodes.

→ Explore all our advice in our article on fungus gnats.

The bright colour of sticky traps attracts flies, which get stuck

Fungus gnats are caught on yellow sticky strips, but larvae must also be treated

Pest Prevention

Good prevention is key to avoiding these pests. Here are some best practices:

• Maintain balanced humidity: overly dry air encourages red spider mites, while excess water attracts fungus gnats.
• Inspect leaves regularly, especially the undersides, to detect infestations early.
• Clean the plant often by wiping leaves with a damp cloth.
• Isolate new plants for a few days before adding them to your collection to avoid introducing pests. Inspect them carefully.
• Quarantine any affected plant from your collection in a separate room while treating it thoroughly.