Berberis · Shrub
Berberis sawfly: Hand-pick larvae or apply biological controls like nematodes; prune affected shoots if severe.
Powdery mildew: Improve air circulation, avoid overhead watering, and treat with a fungicide if necessary.
Aphids: Spray off with water, encourage natural predators like ladybirds, or use insecticidal soap.
Slugs and snails: Use physical barriers like copper tape, beer traps, or iron phosphate pellets.
Vine weevil: Apply nematodes to the soil in autumn and winter to control larvae.