What's eating my nymphaea 'marliacea albida'?

Nymphaea 'Marliacea Albida', a classic white hardy water lily, is susceptible to the standard Nymphaea pest suite. Water lily aphids blacken pads and suppress flowering, water lily beetles graze characteristic slots into leaves, China mark moth caterpillars cut leaf sections, and ducks or geese can shred foliage. Physical removal and fish stocking are the safest and most effective controls.

Dense dark colonies on pads and buds; sticky honeydew, leaf yellowing, and reduced flower production in bad years. Hose aphids off pads into the pond for fish; briefly submerge leaves; do not spray insecticide in or near a wildlife pond.

Elongated grazing slots on pad surfaces; black slug-like larvae and small brown beetles both cause damage from spring to late summer. Hose larvae into water; submerge pads for 24 hours; cut back and remove dead pondside vegetation in autumn to reduce overwintering sites.

Neat circular cut-outs from pad margins and surfaces; floating oval leaf-fragment cases on the water identify the pest. Hand-remove cases; healthy fish populations keep numbers low; no chemical treatment recommended in garden ponds.

Pads grazed down to stubs; flowers eaten before opening; rhizomes disturbed or entirely uprooted. Stretch monofilament or mesh netting just above the water surface; growing in a deeper-water position reduces waterfowl access.