The Australian moth Teia anartoides Walker has been the target of a major eradication program in Auckland, New Zealand. Information on cold torpor and dispersal was needed to help interpret catches of sterile and wild males in female-baited delta traps operated in a grid of up to 1,696 traps at 500-m spacings across the city. Laboratory experiments indicated male flight was enabled at temperatures above 17°C (confirmed by field trapping of wild and recaptured moths). Male survival in the field or in field cages was determined to be limited to ≈4 d. Sterilization of males for dispersal studies was achieved by exposing male pupae to either 160 or 100 Gy by using 1.25 MeV gamma rays from a Cobalt⁶⁰ source, before release as fluorescent-dyed emerged adults. Dispersal was determined by recapture of males in the trapping grid of 1,696 delta traps baited with virgin female moths and placed at spacings of 50–500 m. Irradiated sterile males dispersed up to a maximum recorded distance of 4,500 m (160 Gy) and 10,000 m (100 Gy). At 100 Gy, the median dispersal distance was 300 m, with 90% of males dispersing 1,600 m or less.