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Brassica chinensis White Cottony Spots
eco White Cottony Spots

Brassica chinensis – White Cottony Spots

Why does your Brassica chinensis have white cottony spots? Diagnose the cause and fix it with our step-by-step guide.

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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 Pak Choi. High humidity and poor air circulation around the dense foliage promote spore germination.

Very Common
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How to confirm: Check if the white spots look like dust that can be rubbed off with your finger.
build How to fix it
shopping_cart Recommended Products
1 Apply an organic fungicide to eliminate existing fungal spores and prevent further spread across the foliage.
Bonide Captain Jack's Copper Fungicide 32 oz
Bonide Captain Jack's Copper Fungicide 32 oz
0.9 L • 1 pcs • Organic
$12
In Stock
2 Improve air circulation around the dense Pak Choi leaves and reduce humidity by spacing plants further apart.
3 Prune and carefully dispose of heavily infected leaves to prevent the disease from spreading to healthy parts of the plant.
Fiskars 5/8" Bypass Pruning Shears
Fiskars 5/8" Bypass Pruning Shears
Cutting Tools
$13
In Stock
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Mealybug Infestation

Mealybugs are small insects that secrete a white, waxy, cottony substance to protect themselves. They suck sap from the tender stems and leaf bases of Brassica chinensis, causing yellowing.

Common
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How to confirm: Inspect the underside of leaves and the base of the petioles for tiny, moving white insects.
build How to fix it
shopping_cart Recommended Products
1 Isolate the affected plant immediately to prevent the mealybugs from spreading to your other greenery.
2 Treat the infestation by spraying the plant with an organic insecticide to eliminate the insects and their waxy coating.
Bonide Captain Jack's Neem Oil 32 oz
Bonide Captain Jack's Neem Oil 32 oz
0.9 L • 1 pcs • Organic
$10
In Stock
3 Gently wipe away visible white cottony clusters from stems and leaf bases using a cotton swab dipped in isopropyl alcohol.
warning

Sclerotinia (White Mold)

This soil-borne fungus produces white, cottony mycelium that can envelop the stems and leaves of Pak Choi. It often leads to rapid tissue collapse and rot in high-moisture environments.

Common
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How to confirm: Look for soft, water-soaked lesions on the stem accompanied by fuzzy white growth.
build How to fix it
shopping_cart Recommended Products
1 Remove and destroy all infected plant tissue and surrounding debris to prevent the fungus from spreading to healthy plants.
2 Apply an organic fungicide to control the spread of the white mold and protect remaining healthy foliage.
Bonide Captain Jack's Copper Fungicide 32 oz
Bonide Captain Jack's Copper Fungicide 32 oz
0.9 L • 1 pcs • Organic
$12
In Stock
3 Improve air circulation and reduce moisture by ensuring plants are not overcrowded and by avoiding overhead watering.

Other Brassica chinensis problems

Your plant might also be experiencing one of these issues:

eco Yellow Leaves chevron_right
eco Brown Leaf Tips chevron_right
eco Drooping Leaves chevron_right
eco Sticky Leaves chevron_right
eco Tiny Black Flies chevron_right
eco Leggy Stems chevron_right
eco Fine Webbing chevron_right
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