Australian Truffle Pest & Disease Newsletter

Issue 2 - September 2016

 

External pinholes - sign of truffle beetle infestation

External pinholes - sign of truffle beetle infestation

Damage to truffle gleba by a truffle beetle larva

Damage to truffle gleba by a truffle beetle larva

'Western truffle beetle' (arrow) with slaters and ladybird

'Western truffle beetle' (arrow) with slaters and ladybird

 

BREAKING NEWS: What is considered to be a native species of truffle beetle has been found in Western Australian truffle orchards. The pest status of the beetle is being quantified. Both larvae and the small brown adults feed within truffles resulting in a honeycomb gallery effect. Adult beetles have been attracted to truffle pieces placed in pitfall traps. More on this insect in future issues.

Introduction

Pest management in truffle orchards is relevant to both the establishment and ongoing maintenance of host trees. Further, the yield and quality of the truffles are affected by invertebrate pests directly and indirectly through their contribution to truffle rot.

We acknowledge the major funders for their support of the project:

  • Rural Industries Research and Development Corporation (RIRDC)
  • Department of Agriculture and Food, Western Australia (DAFWA)
  • Australian Truffle Growers Association (ATGA)
  • Truffle Producers of Western Australia (TPWA)
  • Australian National University (ANU)
  • Department of Primary Industries of New South Wales (DPI NSW)
  • Truffle and Wine Company, Manjimup WA. (Truffle & Wine Co)

The Department of Agriculture and Food, Western Australia is the lead agency in conducting this project and involves a team based in WA and eastern Australia.

The project team is made up of Stewart Learmonth, Helen Collie, Alan Jacob and Alison Mathews of DAFWA, consultant Alan Davey from Advyron RS Innovations, project officer through the Truffle & Wine Co. Manjimup WA, Celeste Linde of the ANU, consultant Anne Mitchell of Manjimup Underground and Ainsley Seago of DPI NSW.

 

The major components of the project are:

  1. Conduct a survey of truffle producers to assess the scope of pests and diseases and their management.
  2. Undertake regular monitoring at selected sites to document the occurrence, seasonality and impact of all pests for the life of the project.
  3. Answer enquiries from all producers to confirm the presence of known pests and diseases as well as to capture any unusual or new pest and disease issues and to provide a conduit for the identification and management options.
  4. Conduct a detailed study of the biology and management of slugs, snails and collembolans to clarify the species involved, their seasonality, damage caused and management options.
  5. Incorporate a review of best management practice for the major pests and diseases of truffles and their host trees in a management manual.
  6. Commence a mapping project to document location and other details of the Australian industry. This will be an ongoing exercise in the life of the project and beyond.

This project has now begun with the survey which is in the process of compilation for WA and near completion of interviews in eastern Australia. Orchard mapping has been completed in WA, and, in concert with the survey, mapping of truffle orchards in eastern Australia is underway. Mapping will be ongoing as information on truffle orchards comes to hand.

If you’re interested in other truffle information produced by the DAFWA they have web page on Cultivation of black truffles in Western Australia.

For any comments or questions in relation to the newsletter, please contact the project manager Stewart Learmonth: Ph (08) 9777 0167; 0417 959 139; stewart.learmonth@agric.wa.gov.au

MyPestGuide Reporter - Truffle Survey

Through contact with Australian truffle growers via the industry survey, general direct enquiries, field activities associated with the project and encouraging growers to use the phone App MyPestGuide Reporter – Truffle survey, we are building a catalogue of pests and diseases of truffles and their host trees.

The MyPestGuide Reporter – Truffle survey is available for download from Google Play and the App Store or online on the DAFWA website.

Details of MyPestGuide Reporter - Truffle Survey

Details of MyPestGuide Reporter - Truffle Survey

The availability of the phone App for growers to interact directly with project officers was mentioned in the first project e-Newsletter together with details on how to install and use the Guide. So far few growers have used this facility.

To encourage growers to use this App, we have produced this one page help guide which we hope will allow growers not so familiar with using their i-Phone to install and use the App:

One page help guide for MyPestGuide Reporter - Truffles

One page help guide for MyPestGuide Reporter - Truffles

Growers may use their computer to make a report, provided it has internet connection. The link for accessing this is https://agspsrap31.agric.wa.gov.au/mypestguide/#/. Please be aware that this may not work on Internet Explorer if you have an old version so please use either Google Chrome or Mozilla Firefox. It is not necessary to Register to be able to make a report – by registering you will have access to your reports on MyPestGuide. If you do not register you will still have access to all shared reports.

To make a report from your computer, select “Create a report”. The user needs to click on the “Send report to…” dropdown box and then scroll right to the bottom of that list to select “Truffle survey”.

In addition to direct access to project officers, to help growers identify pests and diseases encountered in their orchard, we have produced a bulletin available on the DAFWA web site containing photos and brief descriptions of the known major pests. With the increase in the range of pests encountered in the first year of the project, the bulletin has been updated recently and is available at Pests and diseases of truffles and their host trees

DAFWA gateway page pest and diseases bulletin

DAFWA gateway page ot the Pest and Diseases bulletin

 

National Grower Survey

One of the first activities of this new project is a survey of truffle growers. The survey will gather information on pests and diseases as well as different aspects of truffle orchard management and attributes of the orchard. This survey is a critical first step for the project as it will give a fuller picture of the pest and disease incidences and trends in production zones across the country and any management issues being faced by producers. The information gathered will help us target project resources for maximum efficiency.

Survey graphic showing information flow

Survey graphic showing information flow

The survey has been conducted in Western Australia, with 49 growers completing the survey representing approximately 80% of known growers. The results are now being collated and analysed by Anne Mitchell, consultant scientist to the project. These results will be presented at the ATGA national conference in September.

We are now concentrating on the survey of Eastern States growers. Surveys have been completed by more than 60 growers in NSW, Victoria and Tasmania. If you have indicated an interest in being part of the survey you will be contacted by a project team member in the coming weeks – Alan Davey (Advyron RS Innovations, ACT), Anne Mitchell (consultant, WA) or from DAFWA - Helen Collie, Alan Jacob or Stewart Learmonth.

We have contact details for many truffle growers in the east, but if you have not received a call from a member of the truffle project team and would like to take part in the survey, or know of other growers who may have been missed, please get in touch with project manager Stewart Learmonth - Ph (08) 9777 0167; stewart.learmonth@agric.wa.gov.au

From the surveys conducted so far the main “pests” of trees have been a suspected bacterial disease and a borer that attack hazelnuts, as well as establishment pests such as African black beetle. To date oak trees appear to be relatively unaffected by pests and diseases. Slugs and millipedes appear to be the major pests of truffles. The significance of the 'new' truffle beetle is being investigated and will be the subject of ongoing investigation.

Information gathered during the survey will directly inform industry biosecurity planning and management. RIRDC, in partnership with Plant Health Australia (PHA) has developed an Australian Truffle Industry Biosecurity Plan. This plan assists industry preparation should exotic pests or diseases that not yet known to occur in Australia arrive. Early detection of such agents is critical in the decisions and subsequent actions taken such as eradication. Knowing the location of truffle orchards and being able to contact growers is vital in this quest.

Mapping Australian Truffle Orchards

After completing the WA survey, the location of orchards has been updated and includes the location of detailed monitoring sites.

Map showing distribution of WA truffle orchards and monitoring sites

Map showing distribution of WA truffle orchards and monitoring sites

Eastern states’ orchards will be added to a map for all Australian growers after the survey of eastern states’ growers is completed. A map of orchardists responding to date is included here.

The distribution of truffle growers in the eastern states of Australia

The distribution of truffle growers in the eastern states of Australia

 

Field Activities

In the first year of the project, field activities have concentrated on gathering information on the types of pests and diseases in orchards with some information on thier abundance and pest status.

Tree diseases

While we have concentrated more on insect and allied pests of trees and truffles in the first year, some attention was given to identifying the causes of poor tree vigour and adverse symptoms on trees in orchards where growers have requested assistance. This has involved both oaks and hazelnuts trees.

Trying to identify causes of apparent tree diseases is far from straight forward. The possibility that even if the symptoms were initially the results of a primary disease, the presence of such a disease may be masked because over time secondary disease organisms become the dominant agent present. Alternatively, symptoms present may be related to stress through other than optimal moisture or nutrient levels in the soil.

 

Variable growth of oak trees in a truffle orchard

Variable growth of oak trees in a truffle orchard

Oak disorder in a truffle orchard

Oak disorder in a truffle orchard                                      

One other factor related to variability in tree vigour of both oak and hazelnut trees is that trees are sourced from seed that is not true to type. By the very nature of the process to inoculate truffle host trees by collecting seed, the resultant trees will be quite variable genetically. This is often reflected in the range of tree vigour during tree establishment and so is not at all necessarily related to the presence of a primary disease agent. So far even for trees with some apparent symptom that could be considered a disease has yet to be conclusively associated with a primary disease agent that might otherwise be the subject of a management program to improve tree uniformity and vigour.

Tip dieback in a hazelnut tree

Tip dieback in a hazelnut tree

Hazelnut with multiple stems

Hazelnut with multiple stems

One problem where some type of dieback occurs in hazelnut trees appears to be best managed by allowing trees to consist of many stems.

Fauna in truffle orchards and truffle pests

A list of key pests has been developed based on field monitoring in WA orchards by project officers and information from growers, both through the survey and a recent trip to eastern Australia undertaken by Stewart Learmonth.

Tile trap and pitfall trap with monitoring equipment

Tile trap and pitfall trap with monitoring equipment

Close up of a pitfall trap with leaf cover removed

Close up of a pitfall trap with leaf cover removed

 

In Western Australia, tile traps and pitfall traps have been deployed in seven truffle orchards located at Bridgetown, Cowaramup, Manjimup, Pemberton, Northcliffe and Denmark. Two types of traps were used - tile traps to monitor fauna seeking shelter during the day such as molluscs, earwigs and slaters and pitfall traps to capture more mobile fauna such as beetles. During truffle season, pieces of truffle were placed in half the pitfall traps at each site to determine whether truffle feeders might be monitored more efficiently.

Slaters under tile trap

Slaters under tile trap

Slaters and millipedes in a pitfall trap

Slaters and millipedes in a pitfall trap

In terms of numbers, slaters and millipedes were the most abundant fauna recorded. Slugs had been thought to be a major pest from previous reports and this was confirmed by assessment of damage to truffles. However, the traps did not appear to be efficient in monitoring them. Although slaters were recorded in large numbers in one truffle producing orchard, there was no evidence that they were feeding on truffles. There was some evidence that millipedes were attacking truffles but further studies are required to clarify and confirm their pest status.

Examining truffles for fauna and damage

Examining truffles for fauna and damage

 

Also during truffle season on a fortnightly basis, we examined 50 truffles in each of the truffle producing orchards where traps were deployed to record fauna attacking truffles and the extent of damage to truffles.

 

The 'western truffle beetle' adult stage is approximately 3 mm long

The 'western truffle beetle' adult stage is approximately 3 mm long

White larva of 'Western truffle beetle' and honeycombing of truffle

White larva of 'Western truffle beetle' and honeycombing of truffle

 

The most significant discovery of the project to date was the damage caused by a beetle to truffles in the Northcliffe area of WA. We believe it is a native truffle beetle probably feeding on native truffles that may occur in the forests of south west WA. The beetle is about 3 mm long and 1.5 mm wide. It is black and tan and has clubbed antennae. The larval stage is white with a brown head and has three pairs of short almost unseen legs on the thorax. It is thought both larvae and adults feed on the truffle gleba resulting in a honeycomb effect which may render a truffle almost unsaleable.

Further studies are planned to clarify the distribution and biology of the “western truffle beetle” and to investigate management strategies to protect truffles.

In the second year of the project, we will be extending studies to the eastern states. Monitoring and in some cases demonstration studies of management techniques will be undertaken in orchards in New South Wales, Victoria and Tasmania visited by Stewart Learmonth in July/August 2016.

In WA, monitoring will continue in some orchards, but the emphasis of field studies will be on conducting demonstration studies related to improving management of some of the key pests, chiefly slugs and the truffle beetle.

Biosecurity

Dogs used to hunt truffles by contractors need to be considered as a potential biosecurity risk also and go through a sterilising footbath before entering the truffle orchard.

Dogs used to hunt truffles by contractors need to be considered as a potential biosecurity risk and go through a sterilising footbath before entering the truffle orchard.

 

Good on-farm hygiene, or farm biosecurity as it is also known, is important for any agricultural venture. By being aware and following some key steps you can reduce the risk of unwanted insect, plant, animal and microbiological organisms entering your property and possibly causing problems. Poor on-farm hygiene can lead to:

  • reduction of product quality
  • reduction of yield
  • contamination of product with inferior products

Good farm hygiene addresses the movement of vehicles and machinery, people and dogs. It is impractical to stop all pest and disease movement onto your property but you can minimise the risk. Foreign pests, diseases or contaminant fungi are most often brought into orchards in soil and plant material either intentionally introduced or by ‘hitching a ride’ on people, machinery and equipment and/or animals.

You can limit the people who enter the production area on your property to only those that need to enter. When they do enter it is particularly important that they have clean, dirt free, footwear. Having footbaths for cleaning and sanitising footwear at the entrance to the orchard is a good idea.

Likewise, all non-essential vehicles, machinery and equipment should be excluded from the orchard; and should be clean and free of dirt when it does enter. Having a wash down bay makes it easy for vehicles and machinery to be cleaned before entering the orchard, this is particularly important for vehicles that visit other properties such as contractors.  Designated roadways can also reduce the amount of traffic into production areas.

Regular crop surveillance is always a good idea.  It helps you pick up new pest and disease problems early keep on top of any ongoing pest and disease issues as well as track general tree health and management practices.

For detailed information on the DAFWA website refer to Truffle orchard on-farm hygiene.

For information on general farm biosecurity including a template for signage, refer to the Farm Biosecurity website.

2016 ATGA Conference and AGM, Manjimup WA 9 – 11 September

Members of the RIRDC Pest and Disease Project team will be presenting at Grower Workshops on the Friday, a summary of activities at the formal proceedings and participating in field walks on the Sunday morning.

Truffle orchard on a sunny winter's day

Truffle orchard on a sunny winter's day