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Spore production and release of Phytophthora pluvialis and Phytophthora kernoviae peaks in late winter in New Zealand radiata pine stands Red needle cast (RNC) is a significant disease Correspondingly, sporulation of P. pluvialis News , May ), may be most of radiata pine in New Zealand that results and P. kernoviae was significantly greater effective if applied in late summer or autumn. in heavy needle cast and associated growth during cooler periods. Sporulation of Operational scale copper control field trials losses in some years. It is caused by an P. pluvialis was also greater during periods are underway to test optimal spray timing. invasive pathogen, named Phytophthora of wet weather, suggesting water is The rapid build-up of severity within a year pluvialis, that was first detected in important for spore production and release. will make the development of a targeted New Zealand in . Another pathogen, This is probably also the case for spraying regime challenging. Trees may be named Phytophthora kernoviae, is also P. kernoviae, for which there was less data green and appear healthy in autumn, but sometimes associated with similar available than for P. pluvialis. Support for severely affected by RNC by spring. Long symptoms, suggesting that it may contribute this comes from analysis of another dataset term disease monitoring has been to RNC. Phytophthora kernoviae also causes included in the paper, which showed that undertaken at  sites to further investigate another foliar disease, once known as infection of Rhododendron ponticum by the role of preceding and contemporary physiological needle blight but now called P. kernoviae was greater during wetter weather conditions in RNC epidemiology, phytophthora needle blight. periods in Cornwall, UK. with an aim to forecast epidemics. Forest Pathologists at Scion are working to Another interesting outcome of the analysis In conclusion, this study shows that within understand the biology of both pathogens, of the Cornwall dataset was the finding stands of radiata pine in New Zealand, with an aim to develop effective that the seasonal pattern of infection by frequency of rain and temperature are the management strategies. One priority is to P. kernoviae in Cornwall was the opposite two most important weather variables elucidate the timing, and climatic drivers, of that seen for sporulation in New Zealand. driving RNC, with greater spore production of spore production and release. In Cornwall, infection peaked towards the observed as rain days increase at cooler Understanding this will support the end of the summer. In New Zealand, temperatures. The observed seasonality of development of disease forecasting models P. kernoviae was likely limited by warmer spore release, with peaks in winter, indicates and chemical control strategies. and drier summers, compared to limitation that copper treatments in late summer or by colder winter weather in the UK. autumn may be optimal for control. In a recent paper in Forest Pathology we However, observations of spatial and Data from New Zealand also indicated that showed that spore release of both species seasonal variability suggest that regional prior weather conditions were also peaked in late-winter at sites in the central and site specific RNC management may important. A nationwide drought in the and east coast regions of the North Island. be required. This is the same pattern seen for the whole  -  summer preceded a long period Stuart Fraser country in detections from pine needle without detections of P. pluvialis and Scion samples submitted to Scion’s Diagnostic P. kernoviae at the sporulation monitoring Laboratory. The concurrent development of sites and in samples submitted to the Fraser, S, Gomez-Gallego, M, Gardner, J, Bulman, LS, symptoms and spore production suggests Diagnostics Laboratory, while wet summers Denman, S, Williams, NM,  . Impact of weather preceded years with P. kernoviae outbreaks. variables and season on sporulation of that these diseases are polycyclic, i.e. there Phytophthora pluvialis and Phytophthora kernoviae. are several cycles of spore production and Based on the results from New Zealand, Forest Pathology e . infection per year that can lead to significant copper fungicides, shown to be effective outbreaks under prolonged periods of against P. pluvialis and P. kernoviae in favourable weather. previous laboratory assays (Forest Health

Bait buckets used for detection of Phytophthora spores. Mobile spores (zoospores) fall into water in the traps, where they swim towards and infect floating detached pine needles. Pine needles were collected fortnightly and plated onto selective media. Resulting Phytophthora cultures were then identified to species. These traps were placed at five sites in the central and east coast regions of the North Island for three years. Collecting New Zealand’s most enigmatic beetle New Zealand is home to perhaps , beetle species, but few are as enigmatic and sought after as Brounia thoracica. It was described by David Sharp in , who stated it was “…one of the most remarkable beetles yet discovered in New Zealand”. Until recently, this odd little beetle was known from just  specimens collected over the last  years. Then in February this year,  specimens were found in insect traps placed in a small native forest remnant in northern Kinleith forest by the Scion Entomology team. The trapping programme is part of our new project examining biodiversity in plantation forests and is clearly already resulting in some exciting finds.

A flight intercept traps suspended in a tree in a native forest patch in Kinleith forest. resulted in many new national and regional Barrier Island (Aotea). This specimen was records (Forest Health News No. ). It is found on the flowers of a mahoe (Melycitus possible therefore that Brounia is relatively ramiflorus) tree, which is the only other piece common but specialised to the previously of ecological information we have on the under-sampled canopy. species. We can hypothesise from this that the adults may visit flowers in the canopy. It is difficult to infer anything of the biology A female Brounia thoracica. Even their preferred habitat is difficult to of Brounia from related species as it is so define, since they have been collected from Given that so few specimens of Brounia have unique. It belongs to the family cattle-browsed bush on East Cape, coastal ever been collected, it is easy to jump to Chelonariidae, which includes about  kānuka bush along a roadside on Great the conclusion that it must be critically described species globally, mostly from Barrier Island, and now a small piece of endangered. However, there is a big the tropics. The family includes just  genera, remnant bush surrounded by pine in Kinleith. difference between a rare species and a and Brounia, which includes just the one We do not know if they occur in pristine rarely collected species. Our Brounia species, is considered the most primitive. native forest, and they may even prefer poor Indeed, it may represent a completely new specimens were collected specifically from quality habitats. The larvae remain unknown, lineage or belong with another family. Flight Intercept Traps (FITs, which are simple but those of other Chelonariidae species Questions concerning its phylogenetic cross-panels over a funnel and collecting overseas are associated with ants or placement have largely gone untested jar), that we hoisted into the forest canopy termites. This seems unlikely for Brounia, as because none of the existing specimens were with the help of a very large slingshot. Little New Zealand is home to few ant or termite suitable for DNA extraction. We hope to canopy-based collecting has occurred in species and Brounia has not previously been answer these with our new collections in New Zealand, but overseas numerous found in the nests of any of them. In the collaboration with researchers at Manaaki studies have found that the forest canopy meantime, we continue to sample insects Whenua Landcare Research and in the supports a unique community of insects across  sites in Kinleith forest, including Czech Republic. compared to the understory or ground. In the site from which we collected Brounia. tropical rainforests, it is estimated that ~ % So, what do we know about this mysterious Hopefully we will find more of these elusive of beetle species are canopy specialists, beetle? The short answer is very little. The beetles and discover more about their ~ % are ground specialists, and the ten known individuals have all been collected abundance, biology, ecology, and phylogeny. remaining ~% utilise both areas. Sampling from the northern half of the North Island, using canopy traps in Canadian production from Whangarei to East Cape. The last Carl Wardhaugh forests by a team led by Jon Sweeney has individual was collected in  from Great Scion

Newsletter of the Scion Forest Protection team. Edited by Andrew Pugh and Stuart Fraser, Scion, Private Bag , Rotorua , New Zealand. Email: [email protected]. Website: http://www.scionresearch.com/biosecurity