Glycine max White Cottony Spots - Causes & Fixes

Jump to cause: Soybean White Mold (Sclerotinia sclerotiorum) Powdery Mildew Cottony Blight (Sclerotinia related/early stage)

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Soybean White Mold (Sclerotinia sclerotiorum)

This fungal pathogen produces a dense, white cottony mycelium that covers leaves and stems, eventually forming hard, black sclerotia. It thrives in high humidity and cool temperatures during the flowering stage of soybean.

Very Common

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How to confirm: Look for small, dark, pea-like structures (sclerotia) embedded within the white fungal mass on the stem or leaf petioles.

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1 Remove and destroy all infected plant material and any visible black sclerotia immediately to prevent the spread of fungal spores.

2 Apply an organic fungicide to protect healthy tissues and manage existing fungal growth.

Bonide Captain Jack's Copper Fungicide 32 oz

0.9 L • 1 pcs • Organic

$12

In Stock

3 Improve air circulation and reduce humidity around the plants by spacing them further apart and avoiding overhead watering.

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Powdery Mildew

Certain species of powdery mildew create white, flour-like patches on the upper surfaces of soybean leaves. This inhibits photosynthesis and can lead to premature leaf senescence if the infection is widespread.

Common

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How to confirm: Check if the white spots appear as a surface coating that can be rubbed off easily with your finger.

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shopping_cart Recommended Products

1 Apply an organic fungicide to the affected leaves to control the spread of the powdery mildew infection.

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 to prevent the fungal spores from spreading to healthy parts of the plant.

3 Improve air circulation around the soybean plants by spacing them properly and ensuring they are not in overly humid, stagnant environments.

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Cottony Blight (Sclerotinia related/early stage)

Early stages of various soil-borne fungal infections can manifest as fuzzy, white growth on the lower canopy where moisture is trapped. This often precedes more significant stem decay in soybean crops.

Common

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How to confirm: Examine the base of the plant to see if the white growth is concentrated near the soil line or leaf junctions.

build How to fix it

shopping_cart Recommended Products

1 Apply an organic fungicide to the affected area to halt the spread of the fungal growth and protect healthy plant tissue.

Bonide Captain Jack's Copper Fungicide 32 oz

0.9 L • 1 pcs • Organic

$12

In Stock

2 Improve airflow around the lower canopy by pruning dense foliage and ensure the soil surface dries between waterings to reduce trapped moisture.

3 Monitor soil moisture levels closely to prevent the waterlogged conditions that favor Sclerotinia development.