BSPP News Autumn 1999 - Online Edition

The Newsletter of the British Society for Plant Pathology
Number 35, Autumn 1999

BSPP Undergraduate Vacation Bursaries 1999

BSPP awarded Undergraduate Vacation Bursaries to  the following 13 students to work in the lab of a BSPP member over the summer in 1999. Reports by the students on their  projects will appear in the Spring 2000 issue (no. 36) of BSPP News. Details of how to apply for a BSPP  Undergraduate Vacation Bursary for summer 2000 can be found in the BSPP web pages.

Alison Carmichael, University of  Hertfordshire, to work with Avice Hall on "Biocontrol of Leptosphaeria maculans with Cyathus sp."

Angela Feechan, University of Edinburgh, to  work with Gary Loake on "Identification of novel disease resistance genes by functional genomics"

Lorna Hall, University of Strathclyde, to  work with Ruairidh Bain, SAC Auchincruive, on "Resistance of aerial tubers to potato blackleg (Erwinia carotovora subsp. atroseptica)"

Hardip Kaur, University of Birmingham, to  work with Nicola Spence, HRI Wellesbourne, on "Using molecular diagnostics to investigate emerging plant virus problems in  the UK protected ornamentals industry"

Helen Meakin, University of Nottingham, to  work with Paul Dyer on "Population biology of eyespot disease of cereals caused by Tapesia"

Russell Palmer, University of Wales, Bangor,  to work with Jim Duncan, SCRI, Dundee, on "The development of co-dominant markers to study the population biology of Phytophthora infestans"

Steven Piper, Napier University, Edinburgh,  to work with Ulrike Krauss, CATIE, Costa Rica on "Biocontrol of cocoa disease"

Kenneth Ross, University of Aberdeen, to  work with Rob Clayton, SAC Aberdeen, on "Systemic induced resistance to late blight in tomatoes"

Elizabeth Sims, University of Hertfordshire,  to work with Roger Williams, IACR Rothamsted, on "Integrated air sampling and PCR-based assays for the detection of ascospores of Sclerotinia sclerotiorum"

Caroline Smith, University of Nottingham, to  work with John Mansfield, Wye College, University of London, on "Screening of Pseudomonas syringae pv. phaseolicola avr mutants on bean"

Anthony Scott-Tucker, University of  Birmingham, to work with Dez Barbara, HRI Wellesbourne, on "Molecular diversity among isolates of raspberry bushy dwarf virus  and its relation to epidemiology"

David Thomsom, University of Strathclyde, to  work with Mark McQuilken, SAC Auchincruive, on "Distribution of fungicide-resistant strains of Botrytis cinerea in ericaceous plant nurseries in the west of  Scotland and the evaluation of novel fungicides"

Annabel Whibley, Magdalen College,  University of Oxford, to work with Sarah Gurr, Department of Plant Sciences, on "Cyclic AMP signal and germ tube differentiation in  the tomato powdery mildew fungus"

 


1998 BSPP Undergraduate Vacation Bursaries

Applications of Information Technology in Plant Pathology

Nuria Garcia-Flor
University of Hertfordshire

A project entitled Applications of Information  Technology in Plant Pathology was offered by CAB International under the 1998 Undergraduate Vacation Bursary Scheme. CABI is an international, intergovernmental, not-for-profit organization dedicated  to improving human welfare world-wide within the schemes of sustainable development.

To be more specific, I worked in the Information Division at Wallingford, an international centre for the collection, organization and dissemination of information on agriculture, forestry, management of natural resources,  etc. This Division is responsible for producing the CAB Abstracts database and many other electronic and printed information products, but it also undertakes a programme of project development and research.

My job was to help with the creation of world  distribution maps of several important plant diseases for publication in the series Distribution Maps of Plant Diseases. The main activities involved:

  • Researching global distributions of selected plant pathogens from the literature using the CAB ABSTRACTS database (on CD-ROM), Crop Protection Compendium (CABI's multimedia information system), non-CABI databases, primary literature, Internet, etc.

  • Compiling references in support of distribution records in a relational database system (Fox Pro) to strict editorial standards.

  • Generating world maps using GIS software.

  • Producing the text to accompany the maps.

The project took place within a period of eight weeks and during that time the following diseases were mapped:

  • Xanthomonas fragariae

  • Citrus tristeza closterovirus

  • Dasheen bacilliform badnavirus

  • Dasheen mosaic potyvirus

  • Periconiella sapientumicola

  • Mycosphaerella laricis-leptolepidis

  • Peronospora hyoscyami f.sp. tabacina

  • Phytophthora boehmeriae

  • Gibberella zeae

  • Puccinia pelargonii-zonalis

  • Alternaria radicina

Some of these diseases had not been mapped before,  others were an update of previous editions. This allowed me to go through all the mapping procedures. Even though some of the diseases mapped may have  very restricted distributions, others, like Citrus tristeza closterovirus, are spread world-wide - all of them can cause major damage to crops. That is why the Distribution Maps of Plant Diseases are used widely be researchers and for pest risk assessments for plant quarantine purposes.

A notable part of the job is the checking involved in the selection of records and sources of information. Recording an infectious agent as present in certain area  may affect the trade of goods, which implies economic consequences. Maps are updated as new information becomes available and  in response to feedback as in the case of Peronospora hyoscyami f.sp. tabacina, which causes blue mould of tobacco. 

I visited CABI Bioscience at Egham in order to obtain geographic records from key literature sources in the specialist library  and specimens in the Herbarium.

I also had the opportunity to become familiar with some of the other projects that are being developed at the moment such as the Crop Protection Compendium and the Forestry Compendium, as well as the production of the CAB ABSTRACTS database and its updating (screening, abstracting and indexing).

I enjoyed participating in such a project because I  had the chance to learn more about GIS and relational databases while getting involved in the field of plant pathology, and particularly learning about crop protection and plant quarantine.

Being employed at CABI Information was positive,  not only because I was in a friendly working environment, but I also found it rewarding that the maps of plant diseases I helped to produce were going to be a useful tool to scientists all over the world.

For all the above reasons I would like to thank the  BSPP for offering the vacation bursary, and the people who made my placement possible: Dr Avice Hall, Dr Peter Scott and Lucinda Charles, who trained me and helped me daily. I am also thankful to the Crop Protection Team, which accepted me as one of them, and all the people at CABI, who made my stay both a valuable and pleasant experience.


A biotrophy-related gene in Colletotrichum

Gemma Priddey
University of Birmingham

I spent a very productive and enjoyable 10 weeks at Birmingham University studying the Colletotrichum-bean interaction. This allowed me to be introduced to molecular and cellular techniques, and to work with a very  interesting plant-fungal system.

Colletotrichum is a large genus of Ascomycete fungi, containing many species, which cause anthracnose or blight on a wide range of important crop and ornamental plants. Colletotrichum lindemu-thianum, a hemibiotroph, is one of the best-studied species  of the genus. Previous studies have identified a novel protein associated with the intracellular hyphae of C. lindmeuthianum. This is CIH1, which is a proline-rich glycoprotein expressed during biotrophic growth inside living  host cells. My project involved investigations of the CIH1 gene, in particular to see whether its expression could be induced in vitro under conditions of nutrient stress.

After first establishing appropriate methods for  RNA extraction from Colletotrichum cultures, I performed Northern  analyses on samples of RNA from in vitro cultures during a time course. I probed samples with the CIH1 gene, using the gene for glutamine synthetase as a positive control. No CIH1 gene expression was detected in vitro compared with expression in planta. I studied Coomassie blue staining of epidermal  peels to investigate possible protein cross-linking in the plant during infection attempts by C. lindemuthianum. Blue halos of Coomassie staining were observed below some appressoria on samples of the fungus with a disrupted CIH1 gene; there was no labelling of wild type infections.

I would like to thank the BSPP for providing the  financial support for this project and enabling me to get experience of molecular plant pathology. Thanks also to Drs Jon Green and Sarah Perfect and other members of the group for their help and advice on the project.

 


www.bspp.org.uk

BSPPweb has had a major overhaul in the last year.  It has a new image based on the design of Plant Pathology's new sub-A4 cover. BSPPweb's new easy-to-use format gives you quick links to the information you need. You can find:

  • details of forthcoming meetings,  including scientific programmes and registration details

  • information about BSPP's publications,  including the Society's journals Plant Pathology and Molecular Plant Pathology (New Disease Reports coming soon!), as well as  books produced by BSPP

  • information about how to apply to BSPP's  various funds (Travel, BSPP Fellowships and Vacation Bursaries, as well as the P.H. Gregory Prize)

  • the Members Database, giving contact  information and interests of BSPP members (database only available to members of BSPP)

  • how to contact BSPP and the members of  its board

Several groups of plant pathologists have started  to use BSPPweb, for instance PhytophthoraWeb, the Scottish Mycology and Plant Pathology Club, the Molecular Biology of  Fungal Pathogens group and others. BSPPweb also hosts the web site of the International Society for  Plant Pathology. We'd like to encourage more groups to use this service to promote their area of special  interest.

Since the 1998 International Congress of Plant  Pathology, the use of BSPPweb has increased by 50%. This emphasises the increasing importance of the internet in  communication. We intend to exploit the potential of BSPPweb for the benefit of members. We welcome members' suggestions  and contributions. 

Adrian Newton, Scottish Crop Research  Institute

John Clarkson, Horticultural Research  International

 


People and Places

Aberystwyth

Aberystwyth has long been a centre for plant  pathology research under the tutelage of Ellis Griffiths, D. Gareth Jones and others in the former department of Agricultural  Botany. Following restructuring of the life sciences at Aberystwyth, there has between some moving about  between the university's two campuses but we are now re-united as a `virtual' institute in the recently-formed  Aber BioCentre (ABC; http://www.aber.ac.uk/~abcwww/). As well as members of the Institute of  Biological Sciences (IBS) on the main campus and the Welsh Institute of Rural Studies (WIRS) on the Llanbadarn campus, the  ABC includes the scientists at nearby IGER (Institute of Grassland and Environmental Research), and is proving  to be very successful in fostering collaboration on several fronts between members of the three institutes.

Although things have been a little quiet in recent  years (scientists at Aber are good at giving the appearance of being laid back, while researching fervently!), 1997 and  1998 have seen a rejuvenation in plant pathology at Aber. The arrival of Professor John Draper and Dr. Luis Mur at IBS  with their large (and rapidly expanding) molecular plant pathology group promises exciting  developments in understanding how the diverse strategies employed by the plant to neutralise a potential pathogen are  regulated. They are focusing on action of chemicals signals synthesised by the plants following the elicitation of  the hypersensitive response, including the roles of hydrogen peroxide in host cell-death defence gene activation, as well  as the action of salicylic acid in boosting plant defences in toto.

Having previously focused on pathogens of model  dicot species, the move to Aber and links with IGER have provided an opportunity to study these mechanisms in !cereal and  grass species too. The group has several commercial links and it is hoped that will their work will  contribute to the development of novel forms of field resistance based on sprays, which may mimic the action of  endogenous defence signals, or genetically modified crops.

Meanwhile at IGER Tim Carver continues to excel  with his work on powdery mildew of barley and his worldwide network of collaborators. The mystery of what goes on when a  mildew conidium meets the leaf surface is being steadily unravelled. Elwyn Jones maintains his involvement in  the UK cereal pathogen virulence survey as well as WG1 of the COST Action 817 programme. Hywel Roderick  is studying crown rust in forage grasses, with particular emphasis on identifying resistance genes in  perennial ryegrass and the introgression of resistance factors from Festuca into Lolium. Brian Clifford is due to retire in May this year after  32 years service.

Back at the university Peter Jenkins and Malcolm  Leitch (WIRS) continue their interests in the epidemiology of foliar pathogens and the role of sulphur as a fungicide  adjuvant respectively.

Gareth Griffith (IBS), destined never to escape  from Aber, has returned to his original interest in cocoa pathology (mainly witches' broom disease) with two projects funded  by Cocoa Research UK. It is hoped that elucidation of the process which take place during broom formation  by Crinipellis perniciosa will lead to strategies to inhibit the  biotrophic development of the fungus, especially now that the disease  has devastated the Brazilian cocoa industry. He has also recently obtained  funding from MAFF to develop a method for early detection of airborne sporangia Phytophthora infestans using flow cytometry, so that information about inoculum levels early in the growing season can be incorporated into  predictive models for disease spread.

Things are looking up so watch this space...!

Gareth W. Griffith, University of Wales

 


All news of plant pathology and plant pathologists  for the "People and Places" pages is welcome, whether from universities, institutes,  companies or other organisations, or from the U.K. or elsewhere. Let your colleagues  elsewhere know what you're up to!


Central Science Laboratory

By the time this edition of the BSPP Newsletter  hits your desk the summer will be over and the staff of Plant Health Group will be celebrating the third  anniversary of their arrival at the new CSL site at Sand Hutton. We're not sure where those three years have gone  but most of us are now feeling at home in and around the fascinating city of York. In the meantime in  the six months since the last Newsletter, here are a few snippets of our activities in plant  pathology (with a slight hint of entomology).

Back in April, Rick Mumford and Chris Malumphy took part in a week-long quarantine pest and disease workshop in Ljubljana, Slovenia. The workshop was sponsored by the European Union through its Technical Assistance Information Exchange (TAIEX) office. This formed part of an on-going process to help Slovenia meet compliance with EU regulations, prior to becoming an EU Member State early in the new millennium. Rick and Chris gave a number of training lectures to inspectors from the Slovenian Phytosanitary  Inspectorate; introducing them to many of the key European quarantine diseases (and pests - Chris is an entomologist). In addition, they were also able to meet many of the Slovenian scientists who will be providing diagnostic services, passing-on much of the experience gained by CSL in running a quarantine diagnostic service. The visit is due to be followed-up by further specialist training for a number of Slovenian scientists, who will visit CSL in the next 6 to 12 months.

Members of the Crop Disease Research Team have also been out and about. Nigel Hardwick attended the European Association of Potato Research conference in Sorrento in May and presented a poster on `The spatial density of weather stations and the accuracy of potato late blight forecasts'. Nearer home more members of the team descended on the CSL stand at Cereals `99, held this year at Wendy, near Royston. Nigel was joined by Sharon Elcock, Phil Jennings and Judith Turner who demonstrated the results of the cereal disease surveys, including the frequency of use of strobilurin fungicides, as well as experimental data on fusarium ear blight. 

Richard Leach and Jackie Stonehouse were responsible for the splendid plots on display which included pot marigolds (Calendula officinalis), linseed, flax and sugar beet as well as cereals and  oilseed rape.  Judith Turner is currently away on maternity leave and responsibility for her work is now in the capable hands of Sharon Elcock. Ellie Clark, from the Plant Disease Diagnosis Team has joined the Team to provide additional cover in Judith's absence.

In the Plant Health Consultancy Team Claire Sansford made it as far as Australia (see Travel Reports section of this Newsletter). She was invited to speak at the "Plant Health in The New Global Trading Environment" workshop, at the Hyatt Hotel in Canberra, organised principally by the Bureau of Rural Sciences (BRS) in the session "International Perspectives on Research for Incursion Management".  She presented a paper entitled "Pest Risk Analysis in the UK and its use to identify research opportunities for exotic plant pathogens". 

Additionally, she visited the Australian Quarantine and Inspection Service (AQIS) and the National Office of Animal and Plant Health and Food Safety both located in Canberra. She gave presentations on the UK Pest Risk Analyses (PRA) for Tilletia indica (Karnal bunt of wheat) and Urocystis agropyri (flag smut on wheat), with discussions on the UK approach to "incursion" management (management of outbreaks of exotic organisms). In July Claire was awarded a framed certificate from the United States Department of Agriculture for her extensive efforts in peer reviewing their PRA on exports of US milling wheat to China containing teliospores of Tilletia controversa (dwarf bunt) which has been beneficial to the US wheat trade.

It seems that never a summer goes by without some new disease being recorded in the UK. Cereal crops are of course intensively studied and in April this year CSL identified the first outbreak of soil-borne wheat mosaic virus (SBWMV) in the UK. Christine Henry, Gerard Clover and Neil Giltrap amongst others from CSL have been involved in investigating the outbreak. The affected farm is in Wiltshire and the disease was seen in crops of three winter wheat cultivars, Equinox, Savannah and Consort. Surveys of neighbouring farms carried out by CSL and the MAFF Plant Health & Seeds Inspectorate suggest that this is likely to be an isolated outbreak. Symptoms of the disease included patches of dramatic stunting in crops, the extent of which varied from small patches of one metre square to areas of about a hectare. The characteristic mild green to prominent yellow streaking and mosaic symptoms were seen, particularly on the lower leaves and leaf sheaths. Measurements of the effect on yield will be carried-out in the infected fields at harvest.

SBWMV is the type member of the Furovirus group and is transmitted by the soil-dwelling protist, Polymyxa graminis. It has a worldwide distribution and has been found in France and Italy for many years. Losses of yield reported in Italy have reached 70% in durum wheat and it remains a serious problem in both these countries.

Chemical control of the disease is very difficult and uneconomic and growers are generally advised to take precautions to minimise the risk of introducing the disease onto their land. Hope for the future relies mainly on the development and use of partially-resistant cultivars of wheat suitable for the UK. Some wheat cultivars have already shown resistance to SBWMV in trials in France, e.g. Charger and Cadenza. CSL has been funded by the Home-Grown Cereals Authority to carry out field trials on UK wheat cultivars on infected sites in France and Italy starting in autumn 1999. MAFF will oversee hygiene measures at the affected UK farm to limit further spread of the disease.

Any findings of new pathogens (or pests) in the UK should be reported to MAFF (England and Wales), SERAD (previously SOAEFD, for Scotland) or DANI (for N. Ireland) and readers should refer to the previous BSPP Newsletter for contact details.

Claire Sansford

 


University of Reading

Plant Pathology at Reading continues to thrive,  despite the departure last autumn of Dr Mike Deadman to take up a chair in Oman. Last April, Sally Barnes joined Plant  Sciences, to study Botrytis epidemiology as part of a MAFF/LINK funded project in association with ADAS, HRI, Silsoe and  Campbell Scientific. This links also to work on novel green hous claddings being undertaken by Dr Simon  Pearson and co-workers.

Vasso Mavroidi joined Mike Shaw's group in  Agricultural Botany at the same time, to work on fungicide resistance and the effects of mixtures. Richard Metcalfe  achieved his PhD on the same subject last autumn and has gone on to a post-doc funded by Zeneca; Dr Yang Tao from China  is visiting for a year, also with interests in fungicide resistance (and Botrytis!). Work on Septoria and wheat continues with exciting results in both the host-pathogen interaction and cultural control areas - both Bader  al-Hamar and Barry Rodgers-Gray will be finishing Ph.D.s next winter.

Prashant Mishra joined Roland Fox's group in Plant  Sciences last autumn to work on Fusarium diseases, looking at aspects of both diagnosis and epidemiology. Irene  Mutinda gained her Ph.D. on the control of a wild mignonette (Reseda lutea). As this weed of Eurasian origin  infests arable land in South Australia, the work was partially supported by the South Australia Research and Development  Institute, based at the Waite Institute. Since his arrival, Dr Paul Hatcher has become responsible for  research on the biological control of weeds. Another of Dr Fox's postgraduates, Dr Prakash Pradhanang, who  studied the epidemiology and genetics of Ralstonia (Pseudomonas) solanacearum which causes bacterial wilt of potatoes has returned to Nepal but wishes to gain further experience elsewhere. He can be contacted on  prakash@bhuwan.wlink.com.np. Dr Fox has just finshed editing "Armillaria root rot: Biology and  Control" for Intercept Publishers. This comprehsive guide to honey fungus and its management is expected to be published in  October. As well as the Crop Protection Option for the Horticulture M.Sc., Roland Fox (Horticulture)  organises the Crop Protection BSc which continues to grow in popularity particularly with mature and overseas  applicants.

Nematology and tropical pathology, under the  leadership of Drs Simon Gowen and Jeff Peters remain strengths, and we launch our new Crop Protection option for the MSc in  Tropical Agricultural Development this autumn. We are also revising all our MSc degrees, and despite the withdrawal of  the MSc in Technology of Crop Protection, there should be new possibilities created soon -  already there is a Crop Protection option in the Horticulture M.Sc. Plant Sciences is also launching a group of  short courses in aspects of crop proctection including two pathology modules.

So both research and teaching flourish here!

Michael Shaw and Roland Fox

 


Congratulations to Mike Cooke, who has recently been promoted to a senior position as  Associate Professor at University College Dublin.


NIAB Cambridge

Conferences, Courses & Events

NIAB Pathologists were involved in demonstrating at  a very hot "Cereals `99" at Royston and at a very wet "Varieties & Seeds Day" here in Cambridge during June.  At the latter, Rosemary Bayles gave a Seminar on interactions between strobilurins and cereal varieties and Jane  Thomas gave Seminars on seed-borne disease risks and herbage diseases. High disease levels again in arable  crops ensured an almost fanatical interest from farmers in disease identification and control!

John Clarkson continues to organise courses and  entertain (?) visitors: an invasion from Norfolk one Wednesday in July brought both a group of M.Sc. students from UEA and  staff from Morley Research Station to the Cereal Pathology Section. Numerous courses on diseases have  included one held recently for scientists from North Korea, with John Clarkson, Rosemary Bayles, Jane Thomas and  David Kenyon all contributing lectures.

Greg Hilton attended the "Molecular Biology of  Fungal Pathogens" meeting at the aptly named Gregynog in mid-Wales in July and gave a presentation on his research work using  AFLP to find molecular markers for identification of wheat yellow rust virulence factors.

Rosemary Bayles (Secretary), John Clarkson and Greg  Hilton (Committee Members) all presented papers at the annual meeting of the UK Cereal Pathogen Virulence Survey here at  NIAB back in March.


Research

Rosemary Bayles coordinates a large programme of  trials looking at disease control in wheat and barley varieties using strobilurin fungicides. Isolates from these and  other trials are used for research on sensitivity of mildew and yellow rust isolates to "conventional" and  "new" (including strobilurin) fungicides; this is a joint project with SAC Edinburgh. We also have projects studying  diagnostics in Septoria spp and pathogenic variation in S. tritici isolates, the latter including joint work with the  John Innes Centre, being done by a Ph.D. student, Catharine Raitt.

Molecular techniques, eg PCR, are being used  to develop quicker, more accurate diagnostic tests for seed-borne diseases of wheat (Jane Thomas) and for identification of Pyrenophora spp in barley (Emily Taylor).  Jane is also involved in research on pea diseases: notably on the  epidemiology of Mycosphaerella pinodes and on risk identification for  bacterial blight.

Venienti occurrite morbo (Meet the disease  as it approaches) Persius: Satires, 43AD.

John Clarkson


More congratulations!

To the following members of BSPP, who were awarded  OBEs in the Queen's Birthday Honours List in June 1999:

Professor Fred Last, in his role as a former member  of Scottish Natural Heritage for services to environmental science, and

Dr John Gibbs, Head of Pathology, Forest Research,  Forestry Commission.

And congratulations too to Dr Roy Johnson, who has  been awarded a BCPC Medal by the British Crop Protection Council, for helping to control the rust diseases of  wheat through his contributions to the breeding of rust-resistant wheat varieties.

 


Cambridge Mycology and Plant Pathology Club

President: Henry Tribe

Two meetings were held in the Lent Term in the Department of Plant  Sciences, University of Cambridge.

`Disease dynamics of soil-borne plant pathogens: analysis, prediction and control' was presented by Doug Bailey of the Department of Plant Sciences, University of Cambridge on 19th February 1999. The research group at Cambridge had the overall objective of developing and testing a cohesive theory for spatial and temporal dynamics of botanical epidemics at scales ranging from a single plant to whole crops. Simple systems such as infection of radish in sand by Rhizoctonia solani had been used to investigate the dynamics of primary infection.

Take-all of wheat was a more complex system involving primary and secondary epidemics. Models had been developed which explained the dynamics of both epidemics and these had been useful in identifying the importance of factors such as inoculum decay and increases in number of roots in epidemic development. The results of some biological control experiments could now be interpreted in terms of effects on primary and secondary epidemics - providing explanations for experiments that appeared not to have worked as well those that did! Field data is now required to validate the models before using them to optimise disease control practises.

Rod Burke of Novartis, Whittlesford, Cambridge gave a review entitled `Development and field experiences of plant disease activators' on 26th February 1999. CibaGeigy (now Novartis) has screened compounds for SAR (systemic activated resistance) activity since the 1980s, but the idea had been recognised for almost a century. SAR differed from other forms of resistance such as pre-formed barriers or locally activated defensive reactions (eg hypersensitivity, phytoalexins)and was probably present in all plant species. Multiple mechanisms were involved and it was characterised by broad-spectrum activity and long duration (6-10 weeks).

In vitro, compounds with SAR activity typically have no fungicidal activity. They mimic natural reactions; plant mutants lacking SAR activity do not respond to the chemical. There is typically a lag of 3-7 days between application and activation of SAR, but the pathways involved are poorly understood. Salicylic acid builds up after treatment and is believed to be important in the induction of SAR. On barley, SAR reduced penetration, haustorial formation and mycelial growth of powdery mildew, but had no effect on spore germination or appressorium formation.

Commercially, benzothiadiazole has been marketed in parts of Europe and it awaits registration in the UK. This compound is likely to be used for control of wheat powdery mildew, tobacco blue mould, rice blast and banana sigatoka. Experience on wheat indicates that the best results are obtained when applications are made at low disease severity. Control may extend to 10 weeks. Clearly this is a promising approach to control of diseases, which will add the new category of `plant activators' to the classification of chemicals applied to crops.

For further information about meetings in autumn 1999, contact Peter Gladders, ADAS Boxworth. (01954 268230)

Peter Gladders

 


Professor Zahir Eyal

We note with deep regret the death of Professor  Zahir Eyal, on 30th July 1999, after a short battle with cancer. Zahir Eyal was a prominent and influential figure in research on  the Septoria diseases of wheat. He had just completed a review on  this subject which will be published shortly in the European Journal of  Plant Pathology.

The 5th International Workshop on Septoria and Stagonospora Diseases of Wheat, in Mexico in September 1999, will be dedicated to Zahir Eyal. He worked to the end to  help with the Workshop. His death has come as a shock to all of those who knew him well over the years through his  work on Septoria.

Messages of condolence may be sent to Professor  Eyal's widow, Mrs Yona Eyal, at The Iby and Aladar Fleischman Faculty of Engineering, Tel Aviv University, Ramat  Aviv 69978, Israel, or at yona@eng.tau.ac.il.