Chrysanthemum Derlei White White Powder - Causes & Fixes

Jump to cause: Powdery Mildew Mealybugs Spider Mite webbing

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Powdery Mildew

This is the most common cause for white spots on Chrysanthemums, caused by fungi like Podosphaera xanthii. It appears as a flour-like coating on leaves and stems, often triggered by high humidity and poor air circulation.

Very Common

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How to confirm: Inspect if the white patches can be rubbed off easily with your finger or if they appear as a fuzzy coating.

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1 Apply an organic fungicide to eliminate the fungal spores and prevent the spread of the mildew across the plant.

Bonide Captain Jack's Copper Fungicide 32 oz

0.9 L • 1 pcs • Organic

$12

In Stock

2 Prune and dispose of heavily infected leaves to reduce the fungal load and improve airflow around the foliage.

3 Increase air circulation around the plant and avoid overhead watering to keep the leaves dry and reduce humidity.

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Mealybugs

These small insects secrete a white, waxy, cottony substance to protect themselves. On Chrysanthemums, they often cluster at the nodes or under leaves and can cause leaves to yellow and drop.

Common

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How to confirm: Look for tiny, slow-moving white insects tucked into the leaf axils or near the base of the flower heads.

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

2 Use a cotton swab dipped in isopropyl alcohol to manually remove the visible white, waxy clusters from the nodes and leaf undersides.

3 Apply an organic insecticide spray to the entire plant to eliminate any remaining insects and larvae.

Bonide Captain Jack's Neem Oil 32 oz

0.9 L • 1 pcs • Organic

$10

In Stock

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Spider Mite webbing

While not a powder itself, extremely fine webbing from spider mites can look like a dusty or white film on the plant surface. This is usually accompanied by tiny yellow stippling (dots) on the leaf surfaces.

Common

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How to confirm: Hold a white piece of paper under a leaf and tap it to see if tiny dark specks fall onto the paper.

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shopping_cart Recommended Products

1 Apply an organic insecticide/miticide spray to the plant to eliminate the spider mite population and destroy any remaining eggs or larvae.

Bonide Captain Jack's Neem Oil 32 oz

0.9 L • 1 pcs • Organic

$10

In Stock

2 Gently wipe the leaves with a damp cloth to remove the fine webbing and any accumulated dust or residue.

3 Increase humidity around the plant and ensure good airflow to make the environment less hospitable for spider mites.