Geranium nodosum White Cottony Spots - Causes & Fixes

Jump to cause: Mealybugs Powdery Mildew Cottony Blotch (Botrytis cinerea)

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Mealybugs

Mealybugs are small, soft-bodied insects that secrete a white, waxy, cotton-like substance to protect themselves. They congregate in the crevices of the knotted stems and leaf axils of Geranium nodosum, sucking sap and causing plant decline.

Very Common

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How to confirm: Use a cotton swab dipped in rubbing alcohol to dab the white spots; if they dissolve and turn brown, it is likely mealybugs.

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1 Isolate the plant immediately to prevent the mealybugs from spreading to your other houseplants.

2 Treat the infestation by spraying the plant with an organic insecticide or neem oil to kill the insects and remove the waxy coating.

Bonide Captain Jack's Neem Oil 32 oz

0.9 L • 1 pcs • Organic

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3 Use a cotton swab dipped in isopropyl alcohol to manually remove visible white cottony clusters from the stem crevices.

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Powdery Mildew

This fungal pathogen manifests as white, flour-like patches on the leaf surfaces. In high-humidity environments favored by some Geranium species, the mycelium spreads across the foliage, eventually causing leaves to yellow and drop.

Common

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How to confirm: Check if the white spots look like a fine dust that can be wiped off with your finger rather than distinct tufts.

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1 Apply an organic fungicide to the affected leaves to eliminate the fungal mycelium and prevent further spread.

Bonide Captain Jack's Copper Fungicide 32 oz

0.9 L • 1 pcs • Organic

$12

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2 Prune and dispose of any heavily infected leaves to reduce the fungal load in your environment.

3 Improve air circulation around the plant and avoid overhead watering to keep foliage dry and reduce humidity.

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Cottony Blotch (Botrytis cinerea)

While often associated with rot, Botrytis can present as fuzzy, grayish-white patches on decaying plant tissue. In the damp microclimates where Geranium nodosum thrives, this fungus can colonize older leaves or damaged stems.

Common

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How to confirm: Examine if the white fuzz is accompanied by soft, brown, rotting spots on the stems or leaf edges.

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1 Prune and remove all affected leaves or stems showing white fuzzy patches to prevent the fungus from spreading to healthy tissue.

2 Apply an organic fungicide to treat the remaining fungal spores and protect the plant.

Bonide Captain Jack's Copper Fungicide 32 oz

0.9 L • 1 pcs • Organic

$12

In Stock

3 Improve air circulation around the plant and reduce humidity to eliminate the damp microclimates that allow Botrytis to thrive.