What's eating my autumn fern?

Autumn Fern (Dryopteris erythrosora) grown as a houseplant is most commonly troubled by spider mites, which thrive when indoor air is too dry and dullen the coppery-red new fronds. Scale insects and fungus gnats also target indoor specimens. Outdoors, slugs may damage young fronds in spring.

Pale bronze stippling on fronds, fine webbing on undersides, loss of the characteristic copper-red colour on new growth. Raise humidity and rinse fronds with water regularly. Apply insecticidal soap or neem oil spray every 7–10 days for three rounds; avoid pyrethroid sprays which can damage ferns.

Brown crusty bumps on stems and frond midribs; sticky residue and sooty mold on lower fronds. Remove scales manually with an alcohol-moistened cotton swab or soft toothbrush, then follow up with neem oil spray monthly until the plant is clear.

Tiny flies hovering around the pot; larvae feeding on roots cause yellowing and wilting despite correct watering. Allow the soil surface to dry slightly between waterings. Use yellow sticky traps for adults and drench the soil with a Bacillus thuringiensis israelensis solution to kill larvae.