IT looks pretty, but Agriculture Victoria says it can devastate the region's waterways.

The agency is urging Mildura, Swan Hill and Kerang residents to report sightings of the state-prohibited weed, water hyacinth (eichhornia crassipes), following recent detections in the area.

Leading biosecurity officer Kaitlin Wright said despite its beauty, water hyacinth was one of the world's worst aquatic...