What's eating my scaly male fern?

Dryopteris affinis (scaly male fern) is a tough, largely pest-resistant garden fern. Slugs and snails may target the soft emerging croziers in spring. Vine weevil is a risk for container-grown plants, where grubs consume roots over winter. Mature established fronds are rarely seriously damaged by any pest.

Ragged holes and torn tips on young unfurling fronds in spring; damage is most visible when croziers are soft and tightly coiled Scatter iron phosphate pellets or use Phasmarhabditis nematodes when the soil is moist and above 5°C; bark mulch and sharp gravel around the crown act as physical deterrents

Adult beetles notch frond edges at night; larvae sever roots at the crown through autumn and winter, causing the plant to collapse and lift out of the ground Apply beneficial nematodes (Steinernema kraussei) in late August to early September; for severe cases in pots, use a systemic insecticide drench; remove and check root balls annually

Irregular holes chewed through frond pinnae, particularly in summer; rarely severe enough to threaten a healthy plant Hand-pick larvae and check frond undersides for egg clusters; encourage natural predators such as ground beetles and birds; Bt spray for heavy infestations