Something Is Eating & Killing My Water Lily

China Mark Moth

• China mark moths (Nymphuliella daeckealis) lay their eggs along the edges and undersides of waterlily leaves. Once the eggs hatch, the larvae remove pieces of the foliage, leaving small holes along the edges of the leaves. Rather than eating these leaf cutouts, the larvae use them as protection and floatation devices. Larvae also feed on the waterlily foliage, creating skeletonizaton of the leaves.

Waterlily Leafcutter

• The adult waterlily leafcutter (Synclita obliteralis) lays eggs near the submersed waterlily vegetation. The eggs overwinter and hatch during the early spring when new waterlily growth begins above the water's surface. These larvae feed on the foliage throughout the spring and summer, eating the leaves that touch the water.

Prevention

• Both China mark moths and waterlily leafcutters destroy waterlily plants' health and appearance, often leading to the death of these aquatic specimens. Promoting plant health helps waterlilies withstand damage due to pests. Prevent pest damage in waterlilies by carefully examining new plants before inserting them in your water garden. Monitor and adjust the water's pH level in your garden, keeping it in a neutral range between 6.2 and 7.4.

Control

• Removing damaged leaves and stems containing larvae controls infestation. Select waterlily varieties resistant to pests, such as White Snowflake and Mrs. S.W. Thomas. Bacillus thuringiensis and Saccharopolyspora spinosa are two types of insecticides that may help control and eradicate pest infestations in waterlily plants.