Savoy Cabbage Convoy F1 White Powder - Causes & Fixes

Jump to cause: Powdery Mildew (Podosphaera tubuae) Fungal Spore Accumulation (Sclerotinia sclerotiorum) Insect Residue or Honeydew

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Powdery Mildew (Podosphaera tubuae)

This fungal disease is characterized by white, flour-like patches on the leaves of Savoy cabbage. It thrives in high humidity and moderate temperatures, often affecting the leaf surface before spreading to the stems.

Very Common

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How to confirm: Inspect the undersides of the crinkled leaves for fuzzy white growth that cannot be easily wiped off.

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

Bonide Captain Jack's Copper Fungicide 32 oz

0.9 L • 1 pcs • Organic

$12

In Stock

2 Prune and remove any heavily infected leaves, ensuring you dispose of them away from your garden to prevent further contamination.

3 Improve air circulation around the cabbage plants and avoid overhead watering to reduce the humidity that promotes mildew growth.

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Fungal Spore Accumulation (Sclerotinia sclerotiorum)

In certain stages of infection, white mycelium can appear on the base or leaves of brassicas. This can lead to stem rot if the fungus penetrates the cabbage tissue.

Common

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How to confirm: Check for any underlying soft, water-soaked tissue or dark lesions at the base of the plant.

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shopping_cart Recommended Products

1 Remove and destroy all infected plant tissue and surrounding debris to prevent the spread of fungal spores.

2 Apply an organic fungicide to the affected area to control the growth of the white mycelium.

Bonide Captain Jack's Copper Fungicide 32 oz

0.9 L • 1 pcs • Organic

$12

In Stock

3 Improve air circulation around the cabbage plants and avoid overhead watering to reduce moisture levels that promote fungal growth.

warning

Insect Residue or Honeydew

Small amounts of white, waxy residue or dried honeydew from pests like aphids can sometimes be mistaken for powder. This is often accompanied by sticky surfaces on the Savoy leaves.

Common

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How to confirm: Look for tiny moving insects (aphids) or a sticky texture on the leaf surface near the white patches.

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shopping_cart Recommended Products

1 Inspect the undersides of leaves for small, soft-bodied insects like aphids or whiteflies that produce sticky honeydew.

2 Apply an organic insecticide spray to eliminate the pest population and clean the residue from the foliage.