Geranium maculatum · Perennial
Vine weevil: Apply a systemic insecticide drench in autumn to control larvae.
Powdery mildew: Improve air circulation and treat with a fungicide if severe.
Downy mildew: Avoid wetting foliage and remove affected leaves promptly.
Capsid bug: Use insecticidal spray or encourage natural predators like ladybirds.
Geranium sawfly: Hand-pick larvae or apply a biological control such as nematodes.