Light brown apple moth, Epiphyas postvittana, is a significant horticultural pest native to Australia, and currently with a limited global distribution. However it can tolerate very heterogeneous climatic and vegetation conditions and has recently invaded California with considerable consequences for US international and domestic trade. A genetic factor that may contribute to its environmental adaptability, and consequently invasive capability, is the phosphoglucose isomerase gene (pgi). This gene codes for a key enzyme in the second step of glycolysis and for which the isozyme composition has been associated with the fitness and dispersal capacity of other moths. As a first step, to determine if this locus is variable within E. postvittana, novel primers were designed enabling access to 957 bp of the coding region across exons 4 to 11 of pgi. Exon-primed intron-crossing (EPIC) primers were then designed to compare sequences of 17 specimens across one laboratory and three wild New Zealand populations from a laditudinal range of ~39-45°S. A total of 70 segregating sites in the exons were found, including 61 synonymous and nine nonsynonymous. Introns 3 to 11 (excluding intron 10) were also sequenced for 13 individuals revealing significant length variation within and between introns and populations. The level of variation revealed here indicates that this could be a useful target gene to assess fitness factors associated with invasibility of E. postvittana.

Light brown apple moth, Epiphyas postvittana, is a significant horticultural pest native to Australia, and currently with a limited global distribution. However it can tolerate very heterogeneous climatic and vegetation conditions and has recently invaded California with considerable consequences for US international and domestic trade. By comparing the climatic conditions of its native (Australia) and long-established (New Zealand) ranges to the rest of the world using CLIMEX, it was suggested that E. postvittana has potential to establish mainly in countries in Central and South America, southern Africa, west Europe and South-east Asia. However, the predicted global distribution of E. postvittana using a new multiple-species-distribution model system suggested that there are additional climatically suitable areas around the world where this species could potentially survive and establish. Our study provides basic but important information for further assessment of the establishment capacity of this species in new habitats, wihch will provide the knowledge required to make science-based decisions in biosecurity.