What's eating my nymphaea 'gonnere'?

Nymphaea 'Gonnere', a fully double white-flowered hardy water lily, is vulnerable to the same aquatic pests as all Nymphaea cultivars. Water lily aphids are the most common problem, coating pads with dark colonies and suppressing bloom. Water lily beetles skeletonise leaf surfaces, China mark moths cut holes in pads, and ducks readily graze the large white blooms and pads in open ponds.

Dark aphid masses on pads, buds, and open flowers; leaves mottle and curl; double blooms may fail to open fully. Hose colonies into pond water for fish to consume; submerge pads for a day; stock pond with goldfish or rudd.

Brown grazing slots on pad upper surfaces; larvae are dark and slug-like; repeated defoliation weakens rhizomes over time. Wash off with hose; submerge affected leaves for 24 hours; remove dead marginal vegetation in autumn to cut overwintering population.

Neat circular holes cut from pads; floating oval leaf-fragment cases are the most visible sign of infestation. Hand-collect and destroy cases; healthy fish population provides ongoing suppression; no chemical treatment required.

Large showy blooms and pads eaten; plants grazed to the waterline in small ponds where ducks have easy access. Use low monofilament or netting deterrents across the pond surface; position lily baskets in deeper water zones.