Control of the water snail Lymnaea stagnalis in ponds

Abstract: In The Netherlands several plant growers, specialists on the production of water plantssuch as Nymphaea alba and Nuphar lutea for the nurseries and home market, have problems withthe great pond snail Lymnaea stagnalis (Gastropoda; Lymnaeidae). Generally, these plants areimported from outside Europe without any snails. During the production season of seedlings intoa more advanced stage plants are damaged by L. stagnalis, which is an increasing problem. Thedamage consists of leaf damage or destroying the plants completely. Consequently, plants areoften no longer marketable. Normally damage appears in late spring until mid summer.Plant growers using water from canals or other open surface water have serious problems, asthis water is contaminated with this species of snail and eggs. Growers using tap water do nothave snail problems. Nurseries do not accept plants with damage or any contamination withsnails or eggs. The consumers buy infected plants and their ponds have an ideal habitat formultiplication of the snails.Research is focused on the reduction of the water snail population without any impact on theenvironment of the water organisms. Additionally, the products may not be phytotoxic to thewater plants.