What's eating my pelargonium 'ardens'?

Pelargonium 'Ardens' is an older hybrid with bright scarlet-crimson flowers, often grown outdoors or in conservatories. Aphids are its most routine pest on new growth. In the UK, geranium bronze butterfly caterpillars are a significant threat, boring into stems. Whitefly and vine weevil can be problems in sheltered or container situations.

Soft green or grey insects cluster on shoot tips and flower stems, causing stunted growth, honeydew, and sooty mould. Remove with a strong water jet or by hand; apply insecticidal soap or neem oil. Repeat weekly until colonies are gone.

Larvae bore inside stems and buds, leaving frass at entry holes; shoots collapse and flower buds are destroyed before opening. Remove and destroy affected stems immediately. Apply spinosad or pyrethrin spray and inspect buds weekly during the growing season.

Adults and nymphs on leaf undersides cause yellowing; honeydew deposits encourage sooty mould and reduce photosynthesis. Use yellow sticky traps and repeat insecticidal soap sprays. Under glass, introduce Encarsia formosa as a biological control.