Scale Insects and Powdery Mildew on UK Garden Plants: Identification and Treatment

Scale Insects and Powdery Mildew on UK Garden Plants: Identification and Treatment

An elm tree and shrub with fluffy white spots topped by brown, barnacle-like scales, plus a laurel with curled leaves and white powder, indicate two distinct problems: scale insects and powdery mildew, both exacerbated by fluctuating weather.

Scale Insect Control

• Identification: 5mm white fluffy spots with brown oval scales on bark.
• Treatment: Bayer Advanced Tree and Shrub Insecticide soil drench (imidacloprid). Kills systemically within a week; protects for up to a year.
• Note: Scales spread to nearby plants if untreated.

Powdery Mildew Management

• Symptoms: Small leaves with curl and white powder on laurel after pruning.
• Option 1: Wettable sulfur spray (avoid if >35°C/95°F to prevent phytotoxicity).
• Option 2 (Homemade): 1 tbsp baking soda + 1 tbsp cooking oil in 4 liters water. Spray every 5–7 days; mix fresh each time.

Cultural Practices

• Water at soil level, not foliage.
• Improve air flow around plants.
• Remove severely infected leaves.

Both issues are manageable with timely intervention.