These marine plants grow in fine sediment in shallow seas and the pathogen seems to have a worldwide distribution.

They have whiplash flagella and can swim to reach new seagrass plants and can also crawl on the surface of the leaves in an amoeboid way by extending pseudopodia forward.

[2] This parasite causes galls to form in the internodes of the rhizomes of its host seagrasses, species of the genus Zostera.

[2][3] The condition is known as wasting disease, the nodes bunch up together and root development is poor so the plants are more easily uprooted in storms.

The infection of seagrasses by this parasite has been little studied but it is possible that it is a vector, able to transmit disease-causing viruses between plants as happens in some terrestrial species in this genus.