What's eating my pelargonium 'flower of spring'?

Pelargonium 'Flower of Spring', a silver-leaved zonal, faces the same key outdoor pests as other zonals: geranium bronze butterfly caterpillars are the most destructive, followed by aphids on new growth and vine weevil in containers. Whitefly can build up in sheltered or glassed positions.

Caterpillars bore into buds and stems, leaving frass and causing shoot collapse; damage is often first noticed only when a stem wilts. Remove and dispose of infested stems. Apply spinosad or pyrethrin spray. Check flower buds regularly for eggs and small larvae.

Soft-bodied insects colonise shoot tips, distorting growth, excreting honeydew, and potentially spreading virus. Knock off with water; apply insecticidal soap or neem oil. Avoid over-feeding with nitrogen, which encourages the lush growth aphids prefer.

Root-feeding grubs cause wilting and sudden plant collapse; characteristic notched leaves indicate adult feeding. Use pathogenic nematodes in late summer on moist compost. Check root balls when repotting; remove and destroy grubs found.