A common cause Spider mites How to tell
Fine webbing in the leaf joints, tiny moving dots, and a stippled, dusty look to the leaves. The fix
1 Rinse the fronds in the shower, then raise the humidity, which mites dislike, and repeat every few days until they are gone.
2 Skip neem and other oils: they can burn fern fronds.
3 If mites keep coming back, use a product whose label says it is safe on ferns.
More about this They thrive in the dry air many homes have.
Isolate it from other plants.
Other possible causes Not a match? Compare the signs below to find the one you have.
Mealybugs White, cottony fluff tucked into leaf joints and along stems, sometimes with sticky residue.
The fix
1 Pick them off with a cotton swab dipped in soapy water (rubbing alcohol can burn fern fronds) and check weekly: they hide.
2 Skip whole-plant soap and oil sprays, which ferns handle badly.
3 If they keep coming back, use a product whose label says it is safe on ferns.
How to get rid of mealybugs →
Scale On a fern, first rule out spore cases: brown dots in regular rows on the underside of fronds are normal and should not be scraped off or treated.
How to tell
Small, brown, limpet-like bumps stuck to stems and the undersides of leaves, often with sticky honeydew. The fix
1 Scrape them off gently with a fingernail or soft toothbrush and keep checking.
2 Skip neem and other oils: they can burn fern fronds.
3 If they keep coming back, use a product whose label says it is safe on ferns.
How to get rid of scale →
Fungus gnats Small black flies run across the soil and fly up when you water.
How to tell
Their larvae live in soil that stays damp. The fix
1 This plant must not dry out, so water from below to keep the surface drier, catch the adults on yellow sticky traps, and treat the soil with a Bti larvicide as its label directs.
How to get rid of fungus gnats →
Fungal leaf spot Brown or black spots, often with a yellow halo, usually after the leaves stayed wet or the soil was overwatered.
The fix
1 Remove affected leaves, improve airflow, and water the soil rather than the leaves.
2 Keep the soil evenly moist as this plant needs: wet leaves, not moist soil, spread leaf spot.
Sunburn (not a pest) Dry, bleached, or brown patches only where strong direct sun hits the leaf, with no bugs or webbing.
How to tell
Holly fern wants bright, indirect light. The fix
1 Move it back from the glass, out of the strongest sun.
The Botanicaly app
A next step for your holly fern. Take a photo in the free app: your first health check looks at your plant and tells you what to do next.
Get the app → Scan with your phone to get the app.
Last reviewed: 26 October 2026
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