Phytophagous insects on broadacre sugarcane in Papua New Guinea.

Phytophagous insects associated with sugarcane at the first plantation established in Papua New Guinea (PNG) at Ramu Sugar Ltd, Gusap are listed, with notes on pest status. Almost all are native to PNG and most do not cause significant loss. . Noctuid and pyralid caterpillars and a weevil larva, which bore in sugarcane stems, are the most damaging. Root-feeding cicadids and a white grub also freguently reduce yield. Two plant-hoppers vector are potentially devastating disease organisms, including one that was previously unknown These insects and three disease organisms place major constraints on production. In the pas, t it was suggested that PNG species that co-evolved with sugarcane - considered to have originated in PNG from the ancestral form Saccharum robustum - would severely damage commercial plantations. Species present now that large scale production is established seem representative of the families that adapt to sugarcane in the rest of the world. None seem dependent on sugarcane, despite prolonged opportunity for associations to evolve. The adaptive nature of these fauna suggests to us that priority pest lists based on species infesting sugarcane elsewhere are misleading. Perhaps the size of family groupings of pests, and not only from sugarcane, is a more relevant determinant of quarantine risk.