Officials are now focusing on long term management of the plant disease, which was first detected on the mainland in a Kerikeri nursery in April last year.
Neither Biosecurity NZ nor AsureQuality would reveal how many staff had worked on the surveillance programme, which in the early stages involved plants being destroyed.
Project Crimson conservation manager Caroline Wallace said so far the disease did not appear to be as severe on pohutukawa and rata as first feared. Project Crimson's mission is to protect the two species.