Native tree extinctions feared as myrtle rust spreads

Areas of New Zealand may see localised extinctions of native trees as myrtle rust continues to spread. It's been just over a year since the invasive plant pathogen was detected in New Zealand. It first turned up on Kermadec pohutukawa on subtropical Raoul Island. A short time later it was found in nurseries in Northland and Taranaki. Since then it's been found at more than 580 sites - and that number grows daily. Alison Ballance reports on the spread, and the possible long-term effect, of myrtle rust in New Zealand.