People are being encouraged to get into their gardens to check for Myrtle Rust as summer heats up.
It has been two years since the fungus first invaded New Zealand.
Infected plants show typical symptoms including bright yellow powdery spots on the underside of leaves.
The fungus attacks myrtle plants like pohutukawa, rata, manuka and ramarama.
DOC's Fiona Thomson told Tim Dower last Summer they found it spread further throughout the country, becoming more active in warmer weather.
She says this year they want to track how far it's spread beyond that.
LISTEN ABOVE AS FIONA THOMSON SPEAKS TO TIM DOWER