A survey of fungal plant pathogens associated with weed infestations of barberry (Berberis spp.) in New Zealand and their biocontrol potential

Since the introduction and subsequent naturalisation of five species of Berberis into New Zealand, two species, B. glaucocarpa and B. darwinii have become aggressive invaders of both agricultural and native ecosystems throughout many regions. Both are now targets for a biological control program. A survey for pathogens to be used as potential classical or inundative biocontrol agents was initiated on weed infestations in New Zealand. Five species of primary plant pathogens were found to be associated with systemic leaf, flower and/or fruit disease symptoms, Colletotrichum gloeosporioides, C. acutatum, Pestalotiopsis sp., Phomopsis sp., and Sclerotinia sclerotiorum. The aecial stage of a barberry rust, Puccinia graminis, was recorded from the flowers of B. glaucocarpa, which is a new host record for New Zealand.