What's eating my nymphaea 'sioux'?

Nymphaea 'Sioux', a colour-changing yellow-to-red hardy water lily, is prone to the usual Nymphaea pest suite. Water lily aphids cluster on pads and buds, water lily beetles graze slots across leaf surfaces, and China mark moth caterpillars cut disc-shaped holes in pads. Ducks can also damage pads in open ponds. Hosing pests into the water for fish to eat is the go-to control.

Dark aphid colonies on pads and buds causing yellowing, honeydew deposits, and poor flower production through summer. Hose off into pond water for fish to eat; submerge affected pads for 24 hours to drown colonies; avoid pond pesticides.

Elongated brown feeding slots on upper pad surfaces from adults and dark larvae; infested pads eventually rot and sink. Wash larvae off with a hose; submerge leaves for a day; remove overwintering habitat such as dead reeds from pond margins in winter.

Round cut-outs in pads where caterpillars harvest leaf pieces; oval floating cases near the surface are the visible sign. Pick off and destroy leaf cases; rely on fish stocking for ongoing suppression; no chemical control needed in balanced ponds.

Pads and flower buds grazed; stems snapped; plants uprooted in shallow water by dabbling ducks searching for rhizomes. Use monofilament deterrent lines or netting just above water; place baskets in deeper sections where ducks cannot reach comfortably.