Brassica oleracea Spring Hero F1 White Cottony Spots - Causes & Fixes

Jump to cause: Powdery Mildew Mealybug Infestation Sclerotinia (White Mold)

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Powdery Mildew

This fungal disease manifests as white, flour-like patches on the leaves of Brassica oleracea. It thrives in high humidity and moderate temperatures, eventually causing leaves to yellow and deform.

Very Common

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How to confirm: Rub a leaf between your fingers; if the white spots wipe off easily but leave a residue, it is likely powdery mildew.

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1 Apply an organic fungicide to eliminate existing fungal spores and prevent the spread to healthy leaves.

Bonide Captain Jack's Copper Fungicide 32 oz

0.9 L • 1 pcs • Organic

$12

In Stock

2 Improve air circulation around the cabbage plants and reduce humidity by avoiding overhead watering.

3 Remove and dispose of heavily infected leaves to prevent the fungus from spreading through the garden.

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Mealybug Infestation

Mealybugs are small insects that secrete a white, waxy, cottony substance to protect themselves. They congregate in the leaf axils and under leaves of cabbage, sucking sap and weakening the plant.

Common

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How to confirm: Use a magnifying glass to check for tiny, slow-moving insects tucked into the crevices where leaves meet the stem.

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1 Isolate the affected cabbage plant immediately to prevent the mealybugs from spreading to other plants in your garden or indoor collection.

2 Apply an organic insecticide spray to the plant, ensuring you coat the undersides of leaves and leaf axils where the white waxy spots are located.

Bonide Captain Jack's Neem Oil 32 oz

0.9 L • 1 pcs • Organic

$10

In Stock

3 Use a soft brush or cotton swab dipped in isopropyl alcohol to manually remove visible mealybug clusters from the plant stems and leaves.

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Sclerotinia (White Mold)

This soil-borne pathogen produces white, cottony mycelium that can spread across the base and leaves of the cabbage head. It leads to rapid tissue decay and rot in high-moisture environments.

Common

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How to confirm: Check if the base of the cabbage plant feels soft, mushy, or is turning dark/brown under the white fuzz.

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shopping_cart Recommended Products

1 Remove and destroy all infected plant tissue and debris immediately to prevent the fungal spores from spreading to healthy cabbage heads.

2 Apply an organic fungicide to the affected area and surrounding plants to control the spread of the white mold.

Bonide Captain Jack's Copper Fungicide 32 oz

0.9 L • 1 pcs • Organic

$12

In Stock

3 Improve air circulation and reduce soil moisture by avoiding overhead watering and ensuring plants are not overcrowded.