Crassula clavata White Cottony Spots - Causes & Fixes

Jump to cause: Mealybugs Cottony Scale Powdery Mildew

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Mealybugs

Mealybugs are the most common cause of white, cottony masses on succulent species like Crassula clavata. These pests secrete a waxy, white substance to protect themselves while they suck sap from the plant's fleshy leaves and stems.

Very Common

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How to confirm: Use a magnifying glass to check the junctions where leaves meet the stem for tiny, moving white insects.

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1 Isolate the plant immediately to prevent the spread of mealybugs to other houseplants.

2 Treat the affected areas by spraying the plant with an organic insecticide or neem oil to eliminate the pests and their waxy coating.

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3 Use a cotton swab dipped in isopropyl alcohol to manually remove visible white cottony masses from the stems and leaf crevices.

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Cottony Scale

Certain types of scale insects produce a white, fluffy appearance that can mimic cotton. They embed themselves into the thick epidermis of the club-shaped leaves, causing localized swelling or yellowing.

Common

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How to confirm: Gently scrape a white spot with a fingernail to see if there is a hard-shelled insect underneath.

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1 Treat the plant with an organic insecticide/miticide spray to eliminate the scale insects and their eggs.

Bonide Captain Jack's Neem Oil 32 oz

0.9 L • 1 pcs • Organic

$10

In Stock

2 Manually remove visible white cottony clusters using a cotton swab dipped in isopropyl alcohol to prevent further infestation.

3 Isolate the plant from other greenery to prevent the scale from spreading to your other houseplants.

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Powdery Mildew

While less common in low-humidity environments, fungal powdery mildew can manifest as a white, dusty coating on the surface of leaves. This is typically more widespread across the leaf surface rather than concentrated in dense cottony clumps.

Common

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How to confirm: Check if the white substance can be easily wiped off with a damp cloth, leaving a clean surface underneath.

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1 Treat the affected leaves with an organic fungicide to stop the spread of the fungal spores.

Bonide Captain Jack's Neem Oil 32 oz

0.9 L • 1 pcs • Organic

$10

In Stock

2 Improve air circulation around the plant and reduce humidity to create an environment less hospitable to powdery mildew.

3 Prune and dispose of any heavily infected leaves to prevent the fungus from spreading to healthy parts of the plant.