Conventional willow control in wetland and riparian areas of New Zealand is undertaken using cut-stump and/or drill and injection application of glyphosate. The presence of herbicide residues in catchment water supplies has seen the investigation of non-chemical alternatives to poplar and willow control in Auckland water catchment areas. We have demonstrated, in glasshouse trials, the efficacy of an aqueous, gel-based formulation of Chondrostereum purpureum to control the regrowth of crack and grey willow (Salix fragilis and S. cinerea). Chondrostereum purpureum isolate ICMP 16392 (isolated from a Prunus sp.) produced the fastest biomass accumulation in liquid culture. Crack willow was significantly more susceptible to cut-stump infection by C. purpureum than grey willow in the glasshouse trial at the end of the 23-week period. Two different formulations were tested; at the end of the trial, there was no significant difference between them with respect to monthly biomass accumulation. Successful field applications of C. purpureum through cut and paste and drill and injection were confirmed by the presence of fruiting bodies on both treated species. Resprouting ability as measured by shoot number was significantly lower on C. purpureum inoculated stumps.

SummaryKauri Agathis australis, an iconic tree of New Zealand, is under threat from an introduced disease‐causing pathogen provisionally named Phytophthora ‘taxon Agathis’ (referred to as PTA). This soilborne, Pythiaceous species belongs to the Chromista and causes a collar rot resulting in yellowing of the foliage and thinning of the canopy, which eventually causes death of the infected tree. The management and containment of this pathogen requires rapid and reliable detection in the soil. The current method for soil detection utilizes a soil bioassay involving lupin baits and soil flooding in a process that takes between ten and twenty days. We describe a real‐time PCR assay based on TaqMan chemistry for the specific detection of PTA, which targets the internal transcribed spacer (ITS) region of the nuclear ribosomal DNA. This TaqMan real‐time PCR assay could be used with DNA extracted directly from bulk soil samples to enable rapid quantification of PTA within soil. The detection limit was 2 fg of PTA DNA from pure culture, or 20 fg in the presence of DNA extracted from soil. The assay was validated using soil samples taken from a PTA‐infested site and soil spiked with a known concentration of oospores. We conclude that the TaqMan real‐time PCR assay offers a more time‐efficient method for detection of PTA in soil than existing methods.

The South American pampas grasses Cortaderia selloana and C. jubata (Poaceae) are serious weeds in New Zealand, particularly in pine plantations and in indigenous plant communities, where it successfully invades bare ground (including cliffs). A national survey of pampas grasses in New Zealand was initiated in 2008 to identify any herbivores (and their associated predators and parasitoids) and fungal pathogens present. The survey revealed a wide range of native and introduced invertebrates associated with pampas in New Zealand but no specialised pampasfeeding invertebrates were found. The most obvious foliage damage was caused by the larvae of the native flax notcher moth, Tmetolophota steropastis. Plant pathogens found included a range of previously recorded, generalist grass pathogens. Assessment will be made of the biological control potential for the insects and pathogens recovered from pampas.

Endophytic microbial populations in Cirsium arvense were assessed as a first step towards testing the endophyte-enemy release hypothesis (E-ERH) of Evans (2008). Culturing and molecular methods complemented each other, increasing the diversity of the endophytic population detected. The leaves showed the greatest endophytic population diversity within the plant.