Insects used for biological control of the aquatic weed water hyacinth in Papua New Guinea.

Abstract

Water hyacinth ('Eichhornia crassipes) was first found in PNG in the early 1960s. By the late 1980s, it had spread to a number of locatioins including the Lower Sepik River, East Sepik Province, where it was expanding rapidly and causing serious problems for the Lower Sepik River communities. An AusAID funded biological control programme, from 1993 to 1998, resulted in four biological control agents, the weevils Neochetina eichhorniae and N. bruchi, and the pyralid moths Niphograpta albiguttalis and Xubida infusellus being released. The two weevil species caused significant reductions of the weed in PNG while the moth X. infusellus established at one site only with no impact. The second moth N. albiguttalis did not become established. We review the biology of each insect, the introductions, release strategies and monitoring for these biological control agents, especially the three that are now part of the PNG biota.