Cunnamulla water lettuce issues

The water lettuce infestation in the Warrego River at Cunnamulla (~750 km inland from Brisbane) is of ongoing concern. This floating aquatic weed has been present in this location for around 10 years and previous attempts in reducing the infestation have not been successful. Water lettuce is currently present in the Warrego River in an 8 km stretch upstream of the Cunnamulla Weir. Along the main river channel water lettuce occurs as a narrow band along the shoreline. The main infestation can be found in side channels and back waters which are heavily timbered, with stands of dead trees and a large number of living tea trees and casuarina. These timbered areas create a complex habitat with multiple refuges for water lettuce, both in terms of hydrologic and climatic conditions, therefore effectively creating nursery areas that are able to sustain the population.