Geranium cinereum · Perennial
Vine weevil: Apply a systemic insecticide drench in autumn to control larvae in the soil.
Powdery mildew: Improve air circulation and spray with a fungicide if infection is severe.
Downy mildew: Remove affected foliage and avoid overhead watering to reduce humidity.
Capsid bug: Use insecticidal soap or horticultural oil during the growing season.
Geranium sawfly: Hand-pick larvae or apply a biological control like nematodes.