Water lilies are flowering, aquatic plants that come in a variety of bloom colours. Water lilies depend on visiting insects to pollinate flowers. However, some insect pests attack water lilies. Several animals also like eating these plants.
The black aphid and aquatic leaf beetle both feed on water lilies, according to Colorado State University Extension. Animals such as beavers, ducks and deer also eat parts of the water lily. Fish, such as grass carp, sometimes eat water lilies as well.
Aphids suck sap from plant tissue, leaving water lilies yellow or brown with distorted shapes. Aquatic leaf beetles chew holes in the leaves, causing stippling. Larger animals eat water lily leaves, seeds or roots. Heavy feeding that removes most of the leaf may damage water lilies, especially over the course of two to three years.
In a pond garden, keep aphids at bay by spraying lilies with a strong stream of water. Remove aquatic leaf beetle larvae by hand. In both cases, remove severely infested plants to avoid spreading. Put up fencing or plant additional preferred plants as a deterrent to other animals. Contact your local county extension agency or department of natural resources regarding trapping, removing or killing larger water garden pests, such as the muskrat.