Varietal resistance to sugarcane stemborers in Papua New Guinea

Commercial crops of sugarcane at Ramu Agri-Industries, Papua New Guinea, are attacked by several species of moth borers, mainly Sesamia grisescens, Chilo terrenellus and Scirpophaga excerptalis, as well as the sugarcane weevil borer Rhabdoscelus obscurus.  We analysed the results of field trials with the aim of evaluating varietal responses to these borers, and particularly to S. grisescens.  For all species, damage and/or numbers of insects differed significantly among clones in some data sets.  Comparing results among the data sets, consistent differences among the standard clones were apparent for S. grisescens and S. excerptalis but were less clear for C. terrenellus.  There were correlations, both positive and negative, between damage from the different borers.