What's eating my pelargonium tomentosum?

Pelargonium tomentosum (peppermint geranium) is most threatened by aphids and whitefly outdoors, and spider mites when grown indoors. Caterpillars and vine weevils may also attack garden plants. The strong peppermint scent deters some pests but does not repel all of them.

Clusters of soft insects on shoot tips and undersides of leaves; sticky honeydew residue and distorted new growth. Blast off with a strong jet of water; apply insecticidal soap or neem oil spray; encourage ladybirds and lacewings outdoors.

Tiny white moths fly up when plant is disturbed; yellowing leaves with sticky honeydew and sooty mould. Use yellow sticky traps; spray with insecticidal soap or pyrethrin-based spray; repeat every 5–7 days.

Fine webbing on stems and leaf undersides; pale stippling on leaves, especially in warm, dry conditions indoors. Raise humidity, mist leaves, or move outdoors; apply neem oil or insecticidal soap; remove heavily infested leaves.

Notched leaf margins from adult beetles at night; wilting and plant collapse caused by larvae eating roots in containers. Apply nematode drench (Steinernema kraussei) to compost in late summer; repot to inspect and remove grubs by hand.