Sorbus · Tree
Scab (Venturia/Fusicladium): Rake up fallen leaves in autumn to reduce overwintering spores and improve air circulation.
Fireblight (Erwinia amylovora): Prune out infected wood well below visible symptoms during dry weather and disinfect tools.
Aphids: Encourage natural predators like ladybirds or use a strong jet of water to dislodge them.
Powdery mildew: Avoid overhead watering and prune for good air circulation; apply sulphur-based fungicide if severe.
Slugs and snails: Use physical barriers like copper tape or lay down iron phosphate pellets to protect young plants.