What's eating my yellow water lily?

Yellow Water Lily (Nymphaea mexicana) faces the same core pond pest pressure as other Nymphaea: the water lily aphid, water lily beetle, and china mark moth are the primary culprits. Chemical controls should be avoided entirely in a pond setting; physical removal and pond fish are the safest management tools.

Dense colonies on pad surfaces, stems, and buds cause yellowing, leaf curl, and poor flowering. Knock colonies off pads with a strong water jet so fish can eat them; avoid any insecticidal sprays in or near the pond.

Adults and black grubs graze elongate slots into the upper leaf surface; damaged leaves rot and may pull the plant under. Hose leaves so adults and grubs fall into the pond; clear pondside vegetation in autumn to remove overwintering habitat.

Larvae cut oval pieces from pads to form protective cases; affected pads show distinctive round holes and missing flaps. Remove caterpillar cases and larvae by hand; tidy marginal plantings to reduce adult moth populations.