Brassica oleracea gongylodes group White Powder - Causes & Fixes

Jump to cause: Powdery Mildew Alfalfa Mosaic Virus (AMV) Deteriorating Leaf Surface (Salt/Mineral Deposits)

search Possible Causes

error

Powdery Mildew

This fungal disease, caused by species like Podosphaera trittici, manifests as white, flour-like patches on the leaves and stems of Kohlrabi. It thrives in high humidity and moderate temperatures, often spreading rapidly through wind.

Very Common

lightbulb

How to confirm: Inspect the underside of the leaves for fuzzy white mycelium that appears before the upper surface is covered.

build How to fix it

shopping_cart Recommended Products

1 Apply an organic fungicide to the affected leaves and stems 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 immediately, ensuring you dispose of them away from your garden to prevent wind-borne spread.

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

warning

Alfalfa Mosaic Virus (AMV)

While often causing mosaic patterns, AMV can cause chlorotic, pale, or whitish patches on Kohlrabi leaves. This virus is commonly spread by aphids and can stunt the growth of the swollen stem.

Common

lightbulb

How to confirm: Look for irregular light-green or yellowish mottling alongside the white patches on young foliage.

build How to fix it

shopping_cart Recommended Products

1 Inspect the plant for aphids, which are the primary vectors for Alfalfa Mosaic Virus, and treat any infestations immediately with an organic insecticide.

Bonide Captain Jack's Insecticidal Super Soap 32 oz

0.9 L • 1 pcs • Organic

$11

In Stock

2 Remove and destroy heavily infected plants to prevent the virus from spreading to healthy Kohlrabi or nearby crops via insect vectors.

3 Maintain plant vigor and stress resistance by providing balanced nutrition to help the plant cope with the viral load.

FoxFarm Grow Big Liquid Plant Food 1 Quart

0.9 L • 1 pcs

$30

In Stock

warning

Deteriorating Leaf Surface (Salt/Mineral Deposits)

Excessive buildup of mineral salts from hard water or heavy fertilization can leave a white, crusty residue on the surface of Kohlrabi leaves. This is not biological but appears as a white film.

Common

lightbulb

How to confirm: Wipe a leaf with a damp cloth to see if the white substance dissolves or moves easily.

build How to fix it

shopping_cart Recommended Products

1 Flush the soil thoroughly with distilled or rainwater to leach out accumulated mineral salts and prevent further buildup.

2 Switch to a high-quality organic fertilizer and monitor nutrient levels to avoid over-fertilization.