Impatiens walleriana Hook.f. · Perennial
Impatiens downy mildew: Remove and bin affected plants (do not compost). Avoid overhead watering. Improve air circulation. Choose resistant cultivars (e.g. Imara series) or switch to New Guinea impatiens / Sunpatiens at affected sites.
Grey mould (Botrytis cinerea): Improve air flow, avoid overhead watering, remove affected material, do not overwinter in stagnant indoor conditions.
Aphids: Hand removal, soft soap spray, encourage natural predators outdoors; for overwintered houseplants isolate and treat before returning to indoor display.
Vine weevil: Biological control (Steinernema kraussei / Heterorhabditis bacteriophora) for container plants; avoid over-wet compost.
Glasshouse red spider mite: Raise humidity, ventilate, introduce Phytoseiulus if severe; do not overwinter in a dry warm room.