Australasian Association of Nematologists

Regional News

News from the ANIC Nematode collection

The reference collection of plant-parasitic nematodes in Australia, housed at the Australian National Insect Collection (ANIC) within the CSIRO Division of Entomology in Canberra, has continued to grow with the support of the GRDC. The list of genera and species has expanded, and additional populations from different localities and crops added for species already represented. We have material from all over Australia, and have specimens of many potential pest species from overseas as well. We are maintaining links with overseas institutions such as Riverside, Davis, Wageningen, Rothamsted and the International Institute of Parasitology to keep up with the latest developments in systematics of pest species. As part of our commitment to maintaining the links between the collection and researchers all over Australia, we present this update of the status of the collection.

The collection currently consists of:

• over 14 500 specimens of plant-parasitic nematodes on permanent slide mounts, covering different life stages, geographic and host variation of many important species;
• more than 750 samples of bulk extracted specimens fixed and stored in glycerol;
• cryopreserved, living specimens of selected species, mainly Pratylenchus;
• a computer database of all plant-parasitic nematodes in the collection, plus all other species described from Australia;
• a library of over 2300 articles of relevant literature (books and reprints), including species descriptions, also completely computer catalogued.

The specialist curator is Emily Stewart, while I have responsibility for identifications, management and overall development.

The collection forms the basis for my own systematic work and is actively used. I am still working on morphological variability in Pratylenchus, particularly in key characters differing between species and geographically different populations of the same species. I am trying to find reliable ways of distinguishing species, as well as producing a catalogue of the species that occur in Australia. The necessity of doing this was brought home recently when a sample from Western Australia contained some Pratylenchus, which did not fit into any currently known species from Australia. The collection is invaluable when doing this kind of work to check the new specimens against the species currently known, but its usefulness depends on people sending material.

The more comprehensive the collection becomes, the more value it will be used as a resource and repository for nematologists across Australia. I am always seeking further material and specimens. Specimens in culture are best, so that all specimens can be processed in identical fashion and inter-culture variation can be assessed. We will even endeavour to cryopreserve cultures of important species, so that the culture will always be available for genetic analysis, pathogenicity testing and comparison. We can also handle material in other forms (for example bulk soil samples with high counts of particular species of interest, live or fixed sorted specimens, or microscope slides). Original host and location records are also important to the value of the collection. Species identity is a bonus, but if unknown I can identify it for you.

It is important for nematology in this country that the species, specimens and information that people collect now are properly stored so that future nematologists will have access to this resource. In fact it is quite likely that material deposited will be of use to us a few years down the track, so there can be an element of self-help in depositing material. The emphasis on electronic databasing is aimed at ensuring the information remains available and accessible, so with the specialist curator and purpose-built collection halls, the material in the collection will receive the best attention. So take a few minutes to deposit specimens and supporting information will save yourself and the next person a lot of time. And don't let those old slides or tubes sit in the corner until they are broken, dry out or disappear: send them to us, so that they will be cared for and curated until they are needed. Or take a minute to make one extra slide of the material you are currently studying and send it to us. Please feel free to contact myself or Emily to arrange shipment of material - we can be contacted on (02) 6246 4371 (telephone) or (02) 6246 4000 (fax), e-mail mikeh@ento.csiro.au or emilys@ento.csiro.au.

Other news from Canberra revolves around arrivals and departures. Frances FitzGibbon, well known to people from Plant Protection at the Waite Institute, was offered a job working on insect pests of sugar cane in a different program within Entomology, and left as curator of the nematode collection in November. Emily Stewart, the new curator is new to nematodes but has lots of experience with vertebrates, so Mike Hodda is currently infecting her with the nematological bug (if that is not mixing metaphors too much). Nora Galway has finished her PhD with John Curran and left to join AQIS.

John Curran’s work with Nora and Felice Driver on genetic relationships of plant parasitic nematodes continues, with development of molecular diagnostics for nematodes as a priority. The group is working collaboratively with SARDI and VIDA testing out molecular methods.

In October last year, I finished a 2-year study funded by RIRDC into effects of management practices on soil nematodes in a wheat cropping system, including their use as indicators of soil health. In the study three tillage/mulching systems were compared within sites at Harden and Cowra. The final tally of species from this study was 104, including 2 Pratylenchus spp. (neglectus most abundant), but also Tylenchorhynchus (Stunt nematode) in considerable numbers, and Paratrichodorus minor (Stubby-root nematode). The abundances of P. neglectus differed between direct-drill, conventional tillage and stubble incorporation systems at Cowra, but not at Harden. There were large differences in abundance of many of the free-living nematodes among the management systems at both Harden and Cowra, suggesting that there are differences in the decomposition pathways under the different systems, and that nematodes can be sensitive indicators of soil processes which are otherwise very difficult to measure.

Currently, I am completing an electronic key to freshwater aquatic nematodes, sponsored by ABRS. This key will be completed at the end of 1998. Anyone who has an interest in this area who would be willing to test preliminary versions of this key should contact me. All feedback will be very welcome.

Mike Hodda, CSIRO Division of Entomology, Canberra

Museums are facing a dilemma

Health and workplace safety requirements mean we can no longer store specimens in formalin, but must transfer them to alcohol: for many things this has been the normal practice for years. Empirical evidence, however, shows that small free-living and plant-parasitic nematodes do not remain robust in alcohol, but become increasingly flaccid and consequently lose value as preserved specimens.

The question arises as to what is happening with our specimens. Are they deteriorating? Most of the animal-parasitic nematodes are quite large, but some are little bigger than the free-living and plant-parasitic ones. They are all in alcohol. Are these gradually decaying? And what might be happening to them?

As part of her Ph.D. in chemistry at QUT, Jan Gentner has been collaborating with the Queensland Museum seeking to understand what happens when nematodes are placed in alcohol, with or without prior formalin fixation. Her spectroscopic and electron microscope study of nematode cuticle and the preservation fluids in which the worms rest has revealed some troublesome details. Jan's work has shown structural weakening or change in the body wall accompanied by leaching of chemicals (lipids and proteins) into the preserving fluid.

Damage appears to be slight in the short term and for robust specimens it may not prove to be a serious threat. Her work, however, does provide some experimental evidence as to why storing small nematodes in alcohol is contra-indicated. Of course, in the longer term perhaps all the collections are gently fading away. Her study raises serious questions as to how we in Museums go about our long-term preservation duties. More research - of course, but who pays?

Fortunately, at the Queensland Museum we have been able to arrange for a special cabinet, vented to the exhaust fan system, to be built for the plant parasitic nematodes. We are thus able to comply with the new regulations AND keep the worms in formalin.

Lester Cannon, Queensland Museum, Brisbane

NEWS FROM NORTH QUEENSLAND

Nematology has recently undergone an expansion in north Queensland. Work is continuing with the management of burrowing nematode in bananas with the completion of the fourth year of the current research funded by the Queensland Fruit and Vegetable Growers Association of Queensland and HRDC. Linda Phillips has recently joined Tony Pattison at the Centre for Wet Tropics Agriculture at South Johnstone to help with nematicide and enhanced biodegradation trials, fallow management and investigations of organic products to aid the control of burrowing nematode.

Also joining the Queensland DPI staff at Mareeba is Primitivo Aceret. Primitivo is funded by the Tobacco Research and Development Corporation to investigate alternatives to EDB for controlling root-knot nematode in tobacco. This work also includes the further development of the population dynamics and work on damage thresholds of root-knot nematode in tobacco. Primitivo has recently submitted his PhD thesis at the University of Central Queensland looking at techniques of fermentation of several nematode species.

Tony Pattison, QDPI, South Johnstone

NEWS FROM VICTORIA

The Victorian component of the southern region nematology project is making good progress at screening field crop varieties for their resistance/susceptibility to Pratylenchus thornei. Despite the exceptionally dry season in 1997 the field trials still provided useful information. We are continuing with this work in 1998. A summary of the varietal reactions to both P. thornei and P. neglectus has been published in GRDC research updates.

Last September we travelled to Perth for the Nematology workshop and Australasian Plant Pathology conference. Both were very rewarding; scientifically and socially. The organisers are to be congratulated on all their hard work.

Since the last newsletter Grant has been appointed as the Cereal Pathologist/Agronomist at VIDA. In this role he is continuing as the Victorian leader of the root lesion nematode project, but also takes on responsibility for the Victorian component of the Rhizoctonia project, plus some other minor projects.

Grant Hollaway and Russell Eastwood, Victorian Institute for Dryland Agriculture, Horsham

Theme: Challenges & Opportunities in 21^st Century

The International Symposium was organised by the Sugarcane Breeding Institute, Indian Council of Agricultural Research, Coimbatore, Tamil Nadu, during April 16-19, 1998, under the Chairmanship of Dr Usha K Mehta, Head Division of Crop Protection. Seventy Scientists from USA, UK, Egypt, Iran, India and Sri Lanka participated. More than 60 research papers were presented in 10 scientific sessions. The recommendations and suggestions made during the sessions were put together by a panel and they are given here:

1. Mapping and documentation of diversity in nematode fauna in different ecosystems of Asia and Africa was identified as a priority area. As India has ample information on nematode fauna associated with agro-ecosystems, the panel recommended that this information must be documented on priority.
2. The panel considered that variety of beneficial nematodes (e.g. insect-parasitic nematodes) and natural parasites of plant-parasitic nematodes that are present in the African and Asian ecosystems are precious natural wealth of the region. The panel endorsed that scientists must exert extreme caution in international sharing of these organisms and they must strictly follow the guidelines developed by their governments. Steps may be initiated to develop national repositories of the beneficial nematodes and natural parasites of harmful nematodes.

Research Methodology

The panel was concerned that the use of standardised research methodologies and protocols by nematologists in the region is still not as common as it should be. This prevents the scientists from making valid conclusions and from comparing results across locations. The panel recommended that guidelines and protocols for conducting and interpreting laboratory, glasshouse, and field studies particularly in the areas of nematode ecology, resistance screening, nematode IPM, and nematode identification schemes should be developed and disseminated.

Human Resources Development

The panel was concerned that many countries in Africa and Asia still do not have sufficient expertise in nematology to identify, assess, manage, and use the nematode fauna. India has the largest trained human resource in nematology in the world. The panel deliberated that India can greatly assist in expanding the nematology base in countries in Asia and Africa by organising short-term and long-term training courses in nematode diagnosis and management. The International Agriculture Research Centres should be contacted for their input.

Soil Fertility Management

The panel recommended that suppression of nematode-induced damage to plants by soil fertility management must be highlighted. It was evident from the papers presented during the symposium that biological (e.g. mycorrhiza on plantation crops) and chemical (e.g. phosphorus on pigeonpea, gypsum on groundnut) fertilisers tend to reduce the nematode-caused damage. In some cases, increase in crop yield by addition of these fertilisers may be a sum of availability of nutrition to plants and alleviation of nematode-caused damage. The panel also recommended that use of VAM for reducing the losses caused by nematodes must be assessed from a cropping systems perspective.

Research on Entomopathogenic Nematodes

Research on insect-parasitic nematodes needs a greater visibility in Asia and Africa. The work done so far has not made much impact. The panel recommended that a "Working Group" of scientists studying these nematodes in Africa and Asia should be developed to identify partners, research priorities, and to formulate a synergistic workplan. Nematologists at the Tamil Nadu Agricultural University and Sugarcane Breeding Institute, Coimbatore were identified to take the lead.

Nematode Management

The panel was concerned that user-friendly IPM packages for nematode management have either not been developed or not transferred to the growers. Development of IPM packages for important nematode pests (e.g. root-knot, cyst, reniform, burrowing nematodes) of agricultural and horticultural crops must be given high priority.

N.Somasekhar, Ph.D, Organising Secretary,

Third International Symposium of Afro-Asian Society of Nematologists

Nematology Section, Sugarcane Breeding Institute, COIMBATORE-641 007

NEWS FROM NEWS SOUTH WALES

I am Loothfar Rahman and would like to introduce myself to nematologists in Australia. I worked on rice nematodes for 15 years in Bangladesh Rice Research Institute. Now I am working as a Plant Pathologist for the Department of NSW Agriculture since December 1996. Currently I am working on a NSW Ag R & D initiative project entitled "Determination of economic impact of nematodes on grapevine, shoot growth, root health and yield".

Other interest areas: Root-knot and lesion nematodes in grapevines, diagnosis and non-chemical methods of nematode control.

Loothfar Rahman, National Wine and Grape Industry Centre, Wagga Wagga.