Insects such as aphids, midges and the China mark moth love to eat lily pads. The China mark moth is a major pest of the water lily. Other consumers of lily pads include turtles, some species of koi, and Pond and Apple snails.
Aside from animals and insects, water lilies are also susceptible to crown rot, a very contagious disease. Compared to terrestrial plants such as roses and vegetables, lily pads are much more hardy and easier to grow. Most of the issues lily pads face are superficial, do little permanent harm and can be easily controlled or avoided. Environmentally friendly biological agents, such as diatomaceous earth, work very well in preventing most of these problems.