What's eating my woodsia ilvensis?

Rusty woodsia is a small alpine/rock fern grown in well-drained garden situations. Slugs are the primary threat on its small fronds. Aphids occasionally infest new growth. Its compact, rocky habitat provides natural protection from larger herbivores. Container specimens must be watched for vine weevil larvae, which can devastate small root systems quickly.

Fronds nipped back, especially newly emerging ones in cool wet weather Grit mulch around crown deters slugs; iron-phosphate pellets; improve drainage so conditions are less slug-friendly

Sticky residue and distorted croziers; small colonies on undersides Insecticidal soap spray; water jet; avoid high-nitrogen feeds that promote soft sappy growth

Sudden plant collapse; white grubs found in rootball Nematode drench (Steinernema kraussei) in spring or late summer on moist compost