Geranium macrorrhizum · Perennial
Vine weevil larvae: Apply a biological control containing nematodes to the compost in spring and autumn.
Slugs and snails: Use iron phosphate-based pellets or beer traps to reduce populations around the plant base.
Powdery mildew: Improve air circulation and spray with a fungicide or milk solution at first sign of infection.
Geranium sawfly larvae: Hand-pick the larvae or apply a biological insecticide containing spinosad.
Capsid bug: Encourage natural predators like ladybirds or use a horticultural oil spray if infestations are severe.