Phaeocryptopus gaeumannii, the cause of Swiss needle cast of Douglas fir (Pseudotsuga menziesii), has been present in New Zealand for more than 50 years. Although much is now known about this disease, important questions remain.  irstly, symptoms are not spectacular, raising questions about its real importance. Stands still look green so does infection really reduce growth, and if so by how much? Secondly, direct control using aerial spraying is not economic, so what is the best way to manage it? In particular, are there regions in New Zealand where improved varieties of Douglas fir can be established without being too severely affected by the disease?

The most common causal agents of root rot in forest nurseries are species of the oomycete genus Phytophthora. Phytophthora cinnamomi and Phytophthora cactorum  are widely distributed in New Zealand. Phytophthora spp. produce motile zoospores that require free water for dispersal. Although young seedlings of many plant species are susceptible to infection, phytophthora root rot is seldom a problem in plantations in New Zealand.

Earlier work that was undertaken at the beginning of this study has already been published: Predicting sapstain and degrade in fallen trees following storm damage in a Pinus radiata forest. Forest Ecology and Management 260, 1456-1466 - download (.pdf - 383.51 kb)

Pests & disease information database for forestry

The primary objective of this field guide is to assist in the identificatoin and assessment of defect caused by nectria lfute canker in mature trees, with particular reference to pre-harvest invenotry of prunded stems. A secondary objective is to provide an assessmet method for quickly checking the value of batches of sawn timber

This review is funded by the Forest Biosecurity Research Council and written for the New Zealand forest industry. It summarises results of research in New Zealand on needle diseases of plantation pines. Overseas work is described if it has application to New Zealand forestry. The aim is to provide a reference point from which to identify future research needs. These needs are listed and summarised, with the aim of assisting development of a research strategy for foliar pathogens of Pinus radiata. Deliberately, future research needs are not prioritised because it was thought that industry should advise researchers on what research activities should be undertaken, rather than the reverse.

An improved method was developed for extracting DNA from pine needles. The best method involved using some components from a commercial DNA extraction kit, along with enzymatic lysis and a simplified purification step. A significant (> 4–fold) increase in yield was obtained using the new method compared to using either of two popular commercial DNA extraction kits. All DNA extracted was tested for suitability for PCR amplification using pinespecific PCR primers.

The Forest Stewardship Council (FSC) requires that biodiversity in exotic forests and indigenous forests grown for timber or as indigenous ecosystems, including pockets/remnants of indigenous forest, is assessed. The objective of this Forest Health Research Collaborative umbrella project is, therefore, to identify the requirement for and methods preferred by foresters for assessing biodiversity in indigenous ecosystems including pockets/remnants of indigenous forest.

An updated guide with text and illustrations entitled “Field Guide to symptoms of Nectria fuckeliana cankers”. Published in a flip–top format.

Commercially available DNA extraction kits are generally as reliable as a “homemade” lab-based method for extracting DNA from needle lesions infected with Dothistroma. However in experiments to determine the minimum number of lesions required for extraction the success was variable with all methods, although sufficient DNA for PCR amplification could be obtained from as few as one or two lesions. A “whole-genome amplification” method is being trialed which may improve success rates with DNA extraction from single lesions. If successful, this method will be especially useful for herbarium samples.

Block 4 at Te Ngae nursery has recently suffered losses among Pinus radiata seedlings due to Phytophthora root rot. The purpose of this project was to investigate chemical and biological options under controlled environmental conditions for their ability to control root rot of P. radiata seedlings, caused by Phytophthora cinnamomi. This project complements FRST funded studies conducted at Te Ngae nursery where various integrated programmes are being evaluated for their ability to manage root rot under field conditions.

Monitoring of climatic conditions within a radiata pine plantation with a history of PNB highlighted both a large reduction in relative humidity (RH) and an increase in soil temperature over a two–week period towards the end of September and beginning of October 2007.  In laboratory–based experiments, reducing relative humidity from 90+ to 52% reduced needle water content, increased the water potential difference between the roots and needles and resulted in 40% death rate of needles after 10 days at the lower relative humidity. Reducing the RH from initial 65% or 58% to 52% did not adversely affect the plants. Soil temperature had no effect on needle water potential or needle water content.

Release of Broom agents in the South Island

The objective of this study was to resample pruned and unpruned Pinus radiata trees that were first sampled in 2006 and to use a DNA based method, as well as culturing, to detect the presence of Nectria fuckeliana. We wanted to confirm our results from 2006 which indicated that there was no significant difference between pruned and un–pruned trees and the presence of N. fuckeliana, determine if fungal incidence changed over time, and determine if there was a relationship between presence of the fungus and fluting.

Stem malformation, typically developing after pruning, has become a problem in some Pinus radiata plantations in part of the South Island of New Zealand over the last 10 years. Infection through the pruned branch stub may result in extensive stain and decay within the stem, although tree crowns remain green and healthy. Nectria fuckeliana, a Northern Hemisphere fungus which is commonly recorded there as a saprophyte or weak pathogen of species of Picea and Abies, is the most commonly isolated fungus from affected trees. Nectria fuckeliana had not been recorded in New Zealand prior to 1996, although it may have been present for some years prior to that date. Research into management of the disease is on–going, and for up to date advice and recommended strategies contact David Thode at PF Olsen.

During the spring months of September, October and November all the major foliage diseases of Pinus radiata in New Zealand may be seen. Confident separation of these disorders is important so that correct management decisions can be made. Diagnosis at a glance -  this illustrated flier describes the differences between the diseases (Cyclaneusma needle cast, Dothistroma needle blight and Physiological Needle Blight) and also the similarities that can be the source of confusion.  The A4 double–sided leaflet, contains colour photographs showing symptoms on trees and needles. Available as a laminated sheet or trifold leaflet, it is designed for easy field reference. Price: $3.00 per laminated sheet or $1.50 per trifold leaflet

Reports from southern Europe indicate that Pinus radiata planted there is highly susceptible to attack by several European pests of pines. In particular, repeated outbreaks of the pine processionary moth (Thaumetopoea pityocampa) have caused much damage in pine plantations in Spain and adjacent countries. Anecdotal reports suggest that P. radiata is more affected by insect pests than the native pines, although there is limited experimental evidence. We undertook a study that combined (1) a review of published and unpublished information on pests affecting P. radiata in Europe and (2) experimental work on insect pests of P. radiata in plantation forests in the Spanish Basque Country and in south–west France. The objectives were:

• to summarise the key characteristics of European pests of Pinus radiata and the damage they can cause,
• to compare the susceptibility of Pinus radiata and other exotic and native pines to these pests,
• and to discuss the implications for forest biosecurity in New Zealand.

Alien weeds, including exotic grasses, shrubs, vines and trees, pose a serious and increasing threat to all of New Zealand’s ecosystems. Unless current control is improved more than 575 000 ha of high priority conservation land will soon be threatened by weeds. In the longer term, the ecosystem-altering effects of invasive plants will have serious impacts on New Zealand’s indigenous biodiversity and productive sectors, by altering hydrological regimes, disturbing the flow of energy and nutrients, and changing the structure and composition of native communities. The financial cost of weeds is also huge. For example, in 1982 the cost of pastoral weeds alone (in terms of production losses plus weed control expenditure) was estimated to be $393 million per annum, which equates to about $1.1 billion today. Biological control is increasingly being recognised as an important tool for managing New Zealand’s serious weed problems. Successful biological control for mist flower (Ageratina riparia), St John’s wort (Hypericum perforatum), and ragwort (Senecio jacobaea) means it is now uncommon for other control methods to be required. The need for control measures against alligator weed (Alternanthera philoxeroides), Mexican devil weed (Ageratina adenophora), and nodding thistle (Carduus nutans) has also been substantially reduced. This field guide explains how to find and recognise biocontrol agents that have been deliberately and successfully introduced to attack weeds in New Zealand. The most significant of the self-introduced and native species that commonly attack weeds in New Zealand are also covered. Species currently under development are not included but we hope to produce additional pages for them in the future.

A disease incidence and severity survey for Nectria fuckeliana was carried out in Otago and Southland from January to April 2004. A field audit of selected plots showed that at the plot level there were significant errors and the original data were not suitable for detailed analysis. The FHRC commissioned an evaluation of survey methods in order to identify errors and recognise deficiencies so that these are not repeated in future surveys. This report recommends procedures to ensure best practice for forest disease surveys.

This study attempted to determine if initial infection of Pinus radiata by Sphaeropsis sapinea predisposes the tree to infection by Nectria fuckeliana

The development of the Viewpoint method for monitoring forest health was an initiative of CHH Forests. A paper describing the method in more detail and its relationship to the PSP method is included at the end of this report

This report summarises work undertaken in 2002–2004, for the New Zealand Forest Health Research Collaborative, to identify the sex pheromone of the common forest looper, Pseudocoremia suavis (Lepidoptera: Geometridae). Pseudocoremia suavis is a polyphagous native moth whose larvae also eat the leaves of Pinus radiata. In the past P. suavis has been responsible for major deforestation in P. radiata plantations notably at Eyrewell Forest, North Canterbury and in Kaingaroa Forest, Bay of Plenty.

The susceptibility of six plantation and two pasture species of plants, to damping–off caused by Fusarium circinatum and to Fusarium oxysporum, was compared.

Fusarium circinatum is the agent of pine pitch canker disease and can cause damping–off of seedlings in addition to causing canker and dieback of older plants. Fusarium oxysporum is a common inhabitant of nursery soils in New Zealand, causing damping–off and root rot to a number of species when soil moisture is high and conditions are conducive to disease.

Field guide contains extract of pages 40–55; "Other Disorders". Covers various mineral deficiencies and types of damage caused by weather or pesticide

A study was conducted to assess the potential for using elicitors to protect Pinus radiata seedlings against infection with Fusarium circinatum, the causal agent of pine pitch canker. Elicitor treatments, applied either six weeks or one week before inoculation, were compared with a commercial fungicide applied 1 week before inoculation. Treated plants were wounded then inoculated with either 10 spores or 100 spores at the wound site in order to mimic low and high disease pressure conditions. Elicitor treatment and fungicide treatment reduced the onset of disease development, as indicated by a reduction in incidence and lesion length. At low inoculum levels all of the treatments significantly reduced disease incidence and severity. At high inoculum levels there were no significant differences between treatments during the early stages of symptom development. However, by 50 days post inoculation it was apparent that there was a significant reduction in plant mortality on seedlings that had been treated with elicitor at 1 week before inoculation. These results confirm our previous findings that elicitor treatment can reduce the severity of infections caused by F. circinatum. There are indications that the plant response may be overcome by high inoculum pressure, particularly when the duration between treatment and inoculation extends to six weeks. Repeated elicitor applications may be advisable under high disease pressure conditions.

The object of this handbook is to provide a source of reference and an introduction to the routine forestry practice of treating exotic pines against Dothistroma needle-blight.The information provided has been gained from over 30 years of research and experience in operational control of Dothistroma needle-blight.This handbook updates three previous versions,published in 1979,1982,and 1988,and it is hoped that readers will find it a useful reference guide for running a successfulDothistroma control programme.

A model to predict the Dothistroma spray programme was developed by testing the effect of rainfall, raindays, and inoculum in previous season on the percentage of susceptible area sprayed in individual years from 1966 to 2002 at Kaingaroa and Kinleith. For both data sets a multiple regression using average monthly rainfall from November–February (including October or March rainfall if 200 mm or more), total raindays of at least 0.1 mm from November–February, and the percentage of susceptible area sprayed in the previous season to predict area sprayed gave reasonable results. The Kaingaroa data set gave an R2 of 0.53 and for Kinleith R2 = 0.70. Some of the unexplained variation was attributable to incomplete or inaccurate input data, management decisions influencing area sprayed, and, possibly, exceptional climatic events such as a wetter and warmer than average September or April.

The object of this handbook is to provide a source of reference and an introduction to the routine forestry practice of treating exotic pines against Dothistroma needle-blight. The information provided has been gained from over 30 years of research and experience in operational control of Dothistroma needle-blight. This handbook updates three previous versions, published in 1979, 1982, and 1988, and it is hoped that readers will find it a useful reference guide for running a successful Dothistroma control programme.

Plant canopies are often the direct or indirect target during aerial spraying. Therefore, there are benefits from understanding and being able to model the factors influencing spray deposition in canopies. Potential benefits from havingmodels that simulate spray interception by canopies include the ability to define application methods and conditions necessary to maximize spray efficiency (i.e., achieve the biological objective with a minimum dose) and to minimize off–target environmental impacts. An experimental study was undertaken to measure spray interception by a discontinuous radiata pine canopy. Two droplet size treatments (volume median diameters of 596 versus 295 m) were applied using a Jet Ranger helicopter, with eight replications of each treatment. Spray deposition was measured on horizontally oriented plastic tubes, which were threaded onto strings located at different layers through a 3 m high canopy. Other measurements included leaf area distribution within the plot and meteorological conditions, with helicopter flight line location and release height determined from a global positioning system. Spray attenuation through the canopy was greater with the smaller droplet size, with only 34% of the spray reaching the lowest sampling level compared to 46% with the larger droplets. Predictions of spray attenuation by the optical canopy model in AGDISP did not closely match measured attenuation.

If GM establishes in New Zealand and eradication is unsuccessful, then ongoing population suppression will be required. If GM arrives in NZ without its natural control agents, as is most likely, then the population will go through substantial outbreaks. Early introduction of a range of agents, suitable for use in NZ, will be required

This study confirms that exotic plantation forests can provide habitat for a diverse understorey and insect fauna with a large proportion of indigenous species, including some rare or threatened species. Despite the homogeneous character of the land occupied by Eyrewell Forest and the almost identical stand structure and age distribution, there is considerable variation in the understorey among stands.

Of the brush weeds, blackberry (Rubus fruticosus agg.) is second in New Zealand only to gorse, in terms of the volume of herbicide sold for its control. The weed competes with plantation trees (of both major and minor forest species) and interferes with silvicultural activities. A successful biological control programme against blackberry would significantly decrease financial and environmental costs associated with this weed and its control.

Brushtail possums (Trichosurus vulpecula) now occupy most areas within New Zealand that are suitable for plantation forestry. Possums browse the terminal shoots of pine seedlings, bite and strip the bark of young stems to get at the cambial tissue, remove needles and cones, and bend or break terminal shoots and lateral branches in the upper portion of the tree. Damage is most commonly reported from young stands. It rarely kills established trees, but can lead to reduced vigour, loss of apical dominance, and an increased incidence of fungal diseases. Where possums are suspected of damaging pine plantations forest managers need to be able to determine when control is required, which areas should have priority, whether control achieves its goals, and when further control measures will be necessary. Reliable inferences and predictions about possum damage can only be obtained from robust, quantitative data. In this manual we discuss the design of surveys to monitor possum damage in pine plantations, and describe a new method for assessing possum damage to pine trees. Canopy Indicator Assessment is a scoring method that uses ground–based assessment of individual trees to determine the nature and extent of possum damage within pine stands, and the degree to which this is reduced as a result of possum control operations. Options for analysing data are outlined.

Over the last 25 years the Forest Health group at FRI have undertaken a considerable amount of research on Cyclaneusma minus. Much of this work has been published in various papers, and recent work has been documented in unpublished project records. It is proposed to produce a bulletin on Cyclaneusma that covers all the work carried out so far on the biology of the fungus, its effect on growth, and methods of control. The part on biology of the fungus will cover symptoms, infection cycle, and taxonomy of the fungus. There is evidence that there are three strains of Cyclaneusma that affect Pinus radiata in New Zealand, the distribution of these strains will be shown. Research is currently being undertaken on the pathogenicity of each strain, results to date will be presented. Data on the effect of Cyclaneusma on tree growth have been collected from trials at Northland, Auckland, Kaingaroa, East Cape, Wellington, Nelson and Otago. Estimates of the growth loss of individual trees and of stand growth will be made. The incidence and severity of the disease in specific regions will be shown, based on results of aerial surveys and data collected by Forest Health Officers.

Results from trials set up to determine if the disease can be managed by selective thinning will be presented, along with results from trials on chemical control. The effect of pruning and thinning on disease incidence and severity will be discussed. All the research on Cyclaneusma carried out by FRI will be presented in a single published up-to-date document, which will make referring to the disease much easier than referencing separate papers that were published over a span of 10 years.

It gives comprehensive coverage of published records (up to June 1999) of fungal pathogens on tree and shrub hosts in New Zealand. Trees have been liberally interpreted, and disease records have been extracted from the literature for all trees (plantation, exotic, indigenous, fruit, shrubs). The database currently contains 10,487 entries. Set up by Landcare Research New Zealand Ltd

Project 2000-03. Report - Inoculation Studies with the Cypress Canker Fungus Seiridium unicorne

Glasshouse studies were undertaken to investigate the feasibility of developing a protocol for screening field-selected cypress stock for resistance to cypress canker disease. Seedlings of Cupressus macrocarpa were inoculated with two isolates of Seiridium unicorne by inserting pieces of mycelium in agar culture into wounds made in the stem. Both isolates induced tissue damage in all plants, but degree of virulence varied between isolates, as indicated by extent of lesion development and, initially, by the level of foliage browning. Variation was also found in the degree of susceptibility among a number of families of C. macrocarpa, as determined by lesion length. However, family rankings were not consistent when plants were treated with different isolates of S. unicorne. Tissue damage and foliage browning were more severe at higher temperatures.

Project: 2003-02. Report - Assessment of needle–cast diseases using aerial photographs

• Periodic defoliation of radiata pine by the eco–physiological disorder known as Strasseria appears to have increased in frequency over the last 20 years. This disorder, as well as Cyclaneusma needle–cast, results in growth loss. A survey technique was trialed to assess the incidence and severity of Cyclaneusma needlecast from aerial photographs. It was based upon a visual interpretation of very large scale aerial imagery.