The potential for novel pests to attack indigenous plants can be examined in non-native ranges of these plants. We used perennial native New Zealand plant species growing in botanic gardens and on public spaces in southern California to explore new associations between these plants, the bacterium Xylella fastidiosa, and its vector, the invasive insect pest, Homalodisca vitripennis (the glassy-winged sharpshooter), both of which are not yet present in New Zealand. Further, we examined the biocontrol potential of egg parasitoids against H. vitripennis on New Zealand plant hosts in southern California. We make the case for the inclusion of biocontrol as an early-response strategy against H. vitripennis should this pest invade New Zealand, and outline the steps required to make biocontrol part of a rapid-response management plan should an incursion and localized establishment occur.