Chrysanthemum Dunga White Powder - Causes & Fixes

Jump to cause: Powdery Mildew Mealybugs White Mold (Sclerotinia)

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Powdery Mildew

This is the most common cause of white patches on Chrysanthemum leaves, caused by fungal pathogens like Podosphaera xanthii. It thrives in high humidity and poor air circulation around the dense foliage of Autumn Mums.

Very Common

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How to confirm: Look for a flour-like coating that can be wiped off with your finger but eventually covers much of the leaf surface.

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1 Apply an organic fungicide to eliminate the existing fungal spores on the leaf surfaces.

Bonide Captain Jack's Copper Fungicide 32 oz

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2 Prune away heavily infected leaves and improve air circulation around the dense foliage to prevent further spread.

3 Reduce humidity and avoid overhead watering to ensure the foliage stays dry, as moisture promotes mildew growth.

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Mealybugs

These small insects secrete a white, waxy, cottony substance to protect themselves as they feed on the plant's sap. Infestations often appear in the crevices of the stems and under the leaves.

Common

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How to confirm: Inspect the stem junctions for small, slow-moving white bumps that feel slightly sticky or waxy.

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1 Isolate the plant immediately to prevent the mealybugs from spreading to your other houseplants.

2 Treat the infestation by spraying the plant with an organic insecticide to kill the insects and remove the waxy coating.

Bonide Captain Jack's Neem Oil 32 oz

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

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White Mold (Sclerotinia)

While usually accompanied by wilting, early stages of Sclerotinia can manifest as white, fuzzy mycelium on the plant base or lower leaves. This fungus thrives in the damp, cool conditions preferred by Chrysanthemums in autumn.

Common

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How to confirm: Check if the white patches are accompanied by soft, rotting stems and check for small, dark sclerotia (nut-like structures) in the soil.

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1 Prune and remove all infected plant material, especially the fuzzy white mycelium at the base, to prevent the fungus from spreading to healthy tissue.

2 Apply an organic fungicide to control the spread of the mold and protect remaining healthy leaves.

Bonide Captain Jack's Copper Fungicide 32 oz

0.9 L • 1 pcs • Organic

$12

In Stock

3 Improve air circulation around the plant base and ensure the soil surface dries out between waterings to disrupt the damp environment the mold thrives in.