What's eating my mahonia winter sun?

Mahonia 'Winter Sun' is a tough shrub but aphids, rust fungus, and mahonia rust mite can set back foliage. Outdoors, slugs graze on young shoots and vine weevil grubs attack roots. Deer and rabbits generally avoid it thanks to spiny leaves, though hungry deer will browse in winter.

Sticky honeydew, curled or yellowing leaflets, sooty mould on foliage Blast off with a hose; apply insecticidal soap or neem oil; encourage ladybirds and lacewings

Notched leaf margins from adult beetles; wilting and plant collapse from white C-shaped larvae eating roots Apply Steinernema kraussei nematodes to moist soil in late summer; use physical barriers and sticky traps for adults

Ragged holes chewed in soft new growth and young leaves, slime trails present Handpick at night; use copper tape or grit around the base; iron phosphate slug pellets are wildlife-safer

Orange-brown pustules on leaf undersides, upper surface shows yellow spots, premature leaf drop Remove and bin infected leaves; improve air circulation; apply a copper-based fungicide if severe