Begonia grandis · Perennial
Slugs and snails: Use copper tape barriers, iron phosphate pellets, or hand-pick at night.
Powdery mildew: Improve air circulation and spray with a sulphur-based fungicide if severe.
Root rot: Ensure well-draining compost and avoid overwatering; repot in fresh mix if affected.
Aphids: Spray off with water or treat with insecticidal soap or natural predators like ladybirds.
Vine weevil: Apply nematodes to soil in autumn/spring or use systemic insecticides.