What's eating my iris laevigata 'variegata'?

Iris laevigata 'Variegata' shares the pest profile of the straight species but the variegated foliage is particularly attractive to slugs, which cause disproportionate cosmetic damage to the cream-striped leaves. Iris sawfly (UK) and iris borer (North America) remain the most structurally damaging pests. Hand-picking and iron-phosphate bait are the main controls.

Larvae notch leaf edges top-down in the typical staircase pattern, spoiling the ornamental variegated foliage that makes this cultivar distinctive. Hand-pick larvae daily during May–June. Drop in soapy water. Variegated leaves make larvae slightly easier to spot against the pale cream stripes.

Tunneling caterpillars create ragged, water-soaked leaf streaks and invade rhizomes, causing collapse of affected fans and smelly rhizome rot. Cut out and destroy infested rhizomes. Clear old foliage every autumn. Spring nematode drench around rhizomes can reduce borer pressure.

Irregular rasped holes in the variegated leaves are especially visible and disfiguring on this ornamental cultivar, worse in wet conditions at pond margins. Iron-phosphate bait (safe near water and wildlife) placed at the crown. Copper tape around container rims if grown in tubs. Hand-pick at dusk.

Colonies on young shoots cause sticky, distorted new growth and can vector iris mosaic virus, which causes mottled discoloration on the variegated leaves. Blast off with water spray. Attract natural predators. Apply insecticidal soap to foliage only if infestation persists.