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This study provides evidence for frequent and multiple invasions of New Zealand's native grasses by exotic cereal and pasture viruses. Fifteen native and three exotic grasses from 29 North Island and six South Island sites were surveyed for the presence of viruses using enzyme‐linked immunosorbent assay (ELISA). Barley yellow dwarf virus and Cereal yellow dwarf virus (BYDV, CYDV: Luteoviridae) and Cocksfoot mottle virus (CoMV, Sobemovirus) are widespread throughout New Zealand. CoMV, previously considered to have a natural host range restricted to Dactylis and Triticum, was detected in Poa anceps, P. cita, Festuca novae‐zelandiae, and Chionochloa rubra. New virus host reports include BYDV‐PAV in Microlaena stipoides and Dichelachne crinita; BYDV‐MAV in P. cita, F. novae‐zelandiae and Hierochloe redolens; and CYDV‐RPV in P. cita and M. stipoides. Nominal logistic regression analyses showed a correlation between the presence of exotic grass species and virus incidence. Host range experiments for BYDV‐PAV and CoMV were performed with selected native and exotic grasses, and the results are discussed in context of the field‐survey findings.

-The tracheal mite, Acarapis woodi , is an obligate endoparasite of honeybees and a regulated pest in countries where these mites are absent. This work describes the development of a real-time PCR method for detecting tracheal mites in honeybees. The real-time PCR was evaluated for specificity, sensitivity and speed to detect A. woodi , compared to the standard manual thoracic disc method (TDM). The assay detected A. woodi down to a 1 % incidence level in bees and 1000 copies of the target DNA when using plasmid standards. Initial testing showed no cross-reaction with the other two Acarapis species from different geographical regions or with other species of mites associated with bees. However, during extensive testing of bees, a rare population of Acarapis externus mite was identified that did cross-react with the assay. Despite this cross-reaction, the assay has been shown to be a useful screening tool and results are reliable if the TDM is used as a backup to screen hives where a positive signal is obtained.honeybee / tracheal bee mite / Acarapis / automated DNA extraction / real-time PCR