What's eating my polypodium cambricum 'cambricum'?

Polypodium cambricum 'Cambricum' is a handsome crested cultivar of Welsh polypody with the same robust, low-pest character as the species. Slugs and snails can nibble the distinctively lobed fronds when they emerge in autumn. Vine weevil grubs are the main risk if grown in containers. Its tough rhizomes and leathery fronds deter most garden pests.

Holes and ragged tips on newly emerged fronds in late summer and autumn; the ornamental lobed pinnae are particularly visible when damaged Use iron phosphate pellets or Phasmarhabditis nematodes around the plant from late summer; remove mulch and debris that shelter slugs; hand-pick after dark in damp weather

Root destruction by fat cream larvae during autumn and winter causes the plant to wilt and lift out of its pot or container planting Apply beneficial nematodes (Steinernema kraussei) to containers in August–September; repot annually in fresh compost to check for grubs; treat with imidacloprid drench if infestation is confirmed