Soybean Rust work group

meeting held on Thursday 25 July 2002 at 09h00, Pietermaritzburg

  1. Opening

    Dr Liebenberg, an ARC-GCI representative, opened the meeting with a prayer.

  2. Welcome

    The chairperson, Dr J Purchase extended a warm welcome to all present, especially to Ms Stephanie Tweer (KwaZulu-Natal Department of Agriculture and Environmental Affairs), Mr Leon Killian (PRT), Mr Braam Bester (Monsanto) and Mr Thom Steyn (Monsanto) who are newcomers.

  3. Attendance and apologies


    Dr JL Purchase ARC-Grain Crops Institute
    Dr NW McLaren ARC-Grain Crops Institute
    Mr AJ Pretorius ARC-Grain Crops Institute
    Dr AH McDonald ARC-Grain Crops Institute
    Dr AJ Liebenberg ARC-Grain Crops Institute
    Mr AJ de Lange ARC-Grain Crops Institute
    Mr GP de Beer ARC-Grain Crops Institute
    Mr KF Lawrance ARC-Grain Crops Institute
    Mr GJH Scholtemeijer Oil & Protein Seeds Development Trust
    Dr J de Kock Protein Research Foundation
    Mr L Killian Protein Research Foundation
    Mr NJ Vermaak Grain South Africa
    Mr FAS Potgieter Grain South Africa
    Ms ED du Preez KwaZulu-Natal Department of Agriculture & Environmental Affairs
    Mr N van Rij KwaZulu-Natal Department of Agriculture & Environmental Affairs
    Ms S Tweer KwaZulu-Natal Department of Agriculture & Environmental Affairs
    Mr ID Lamprecht Mpumalanga Department of Agriculture, Conservation & Environment
    Prof M Laing University of Natal
    Dr P Caldwell University of Natal
    Mr N Loïc University of Natal (French student)
    Dr FJ Kloppers PANNAR
    Mr A Jarvie PANNAR
    Mr B Bester Monsanto
    Mr T Steyn Monsanto
    Mr A de Klerk AVCASA (Du Pont)
    Mr N Hackland AVCASA (BASF)
    Ms P Kruger Secretary


    Prof ZA Pretorius Department of Plant Pathology UFS
    Mr J Middel Grain South Africa
    Mr C Roose AVCASA (BASF)
    Ms S van der Walt AVCASA (BASF)
    Mr A Bennett Monsanto
    Dr C Levy Commercial Farmers Union

    The meeting was informed that Mr Middel (GSA) will be replaced by Mr Potgieter (GSA) as a member of the SBR Task Team.

  4. Finalisation of agenda

    The agenda was approved, with the addition of points 7.5 and 8.1 to 8.4.

  5. Minutes

    1. Corrections and acceptance

      The minutes of the 2nd meeting of the Soybean Rust Task Team held on Friday, 24 August 2001, were accepted as a true reflection of the meeting.

    2. Matters arising

      1. Set of differentials

        Although Prof Pretorius was not able to attend, he requested that the Chairperson give feedback to the meeting (also see attachment 2).

        • Samples received from Dr Sundar were planted and multiplied successfully.
        • Different isolates were also received from Pannar and ARC-GCI for testing which will commence next season.
        • Prof Pretorius also requested that other role players involved in such testing, to communicate their results / successes to him. Dr Caldwell informed the meeting that they have conducted one trial (in pots) with material received from Dr Sundar.

        Dr Liebenberg commented that in the case of dry beans, it is important to use glasshouse differentials for expression and not field differentials.

        Mr Scholtemeijer referred to a quote from Prof Pretorius (see Attachment 3, page 3 point 5.2.2) and enquired as to whether "opslagplante" were examined or not, and if so, what the results were. Dr Purchase explained that "opslagplante" are volunteer plants that come up early in the season and are then examined to determine whether isolates may occur on the plants.

        The meeting requested that Prof Pretorius be contacted in order to establish whether any work on "opslagplante" has been done by him or any of his personnel.

        Dr Purchase explained that the actual aim is the collection of isolates / samples from volunteer plants. With the availability of differentials, collecting isolates from the volunteer plants and not just within seasons, can commence.

        Regarding the differentials, Dr Caldwell offered excess / surplus seed from their trials to PANNAR for sharing. She also informed the meeting that differential trials were conducted in the glasshouse in order to keep the plants clean for inoculation. Due to the strong air currents in the glasshouse, sprays had to be used to keep the trials clean.

      2. Literature study

        The meeting was informed (attachment 4) that Prof Pretorius has appointed a student to conduct a Literature Study. A draft document has been compiled containing relevant articles to date – the document still needs to be edited before it is finalised. Dr McLaren offered to assist with editing.

        Dr Caldwell also mentioned that International Literature (unfortunately most in Asian languages) is available. She indicated that she has a substantial collection of reprints and that members of the Task Team should enquire with her before ordering what may be expensive copies of articles. The meeting was also informed of a complete Literature Review of Phakopsora pachyrhizi, the causal organism of soybean rust, compiled by Michelle Govender, University of Natal, Pietermaritzburg, April 2002 (attachment 5).

        Dr Kloppers mentioned that the Americans also have a summary available of relevant literature / information (attachment 6).


        1. An index of literature references to be compiled and to be updated and distributed regularly.
        2. All aspects concerning the index / list of literature references to be handled by Dr Caldwell.

          Dr Caldwell

        3. Updates of the index / list to be e-mailed to Ms Kruger for distribution to the SBR Task Team members.

          Ms Kruger

      3. Article

        The meeting requested that all articles, TV- and radio broadcasts, be listed for reference purposes.

        1. Articles

          • SA Grain, September 2001 by Dr Purchase.
          • Om die probleem in die kalklig te stel.
          • Farmer's Weekly, Grain Review by Dr Purchase.
          • Farmer's Weekly by University of Natal.
          • Landbouweekblad, Plant Protection Appendix.
        2. TV broadcasts

          • Dr Purchase reported on GSA TV and "Wen Akker".
        3. Radio broadcasts

          • Dr Purchase appeared regularly on "Radio Sonder Grense".
        4. Farmers' days

          • Cedara hosted a farmers' day on soybean rust where ARC-GCI was also involved (± 100-150 attendees).
          • Pannar also hosted a number of farmers' days.
        5. International exposure

          • Workshop with Dr Sundar (AVRDC) as guest speaker.
          • Presentation by Dr C Levy (CFU) at previous SBR Task Team meeting.
          • Information circulated internationally via e-mails.
      4. Pamphlet

        Pamphlets were sent out to all the relevant role players.

        Mr Potgieter expressed the appreciation of the producers and emphasised the effective manner in which the pamphlets were distributed.


        Mr Vermaak suggested that the pamphlet be placed on the websites of GSA (to be activated on 6 August 2002) and of ARC-GCI.

        Mr Scholtemeijer enquired as to whether the information on the pamphlet is correct and whether it needs to be updated. With the coming season at hand, the pamphlet needs to be updated as a matter of urgency and should contain the most recent and relevant information.

      5. Indicator trials

        Discussed in detail under "Seasonal Feedback" (point 6).

        Dr Kloppers indicated that early plantings were used as indicator trials and that no specific indicator trials were conducted.

        Dr McLaren mentioned that the farmers realize the importance of indicator crops and the need to plant their own indicator crops.

      6. Presentations

        Summaries of the presentations were attached to minutes of the previous meeting.

  6. Seasonal feedback

    1. Overview

      The meeting was informed that Dr Levy was invited to the 2nd Brazilian Soybean Congress where he attended a special SBR Workshop. SBR hit Brazil and Paraguay during March 2002 and last season they had yield losses of approximately 125 000 tons / $25 million. A new International Work Group (IWG) on SBR has been established and Dr Levy nominated Prof Pretorius, Dr McLaren and Dr Kloppers to represent South Africa and participate in the forthcoming events. Dr Levy was invited by the USDA for a workshop in June as they are expecting SBR to break out in the US this summer. Prof Yang (Ohio State University) also forms part of the IWG and has been mandated to organise a meeting.


      Contact to be made with Prof Yang as soon as possible in order for the SBR Task Team to become involved with the IWG and to be placed on the mailing list. Dr Caldwell to e-mail Prof Yang's address to the secretary.

      Dr Caldwell informed the meeting that the University of Natal (UN) has been in contact with the breeding division of the USDA and that they are interested in conducting trials in South Africa. The UN still awaits confirmation of approval. She also mentioned that she will be attending the Congress in Brazil during February 2004.

    2. General discussion

      Questions / Answers

      The issue of Phakopsora meibomiae was raised and whether there is certainty that only the one species exists in South Africa.

      Scientific publications and research confirmed that only P. pachyrhizi exists in South Africa – although the species has not been compared to the Brazilian species, a second species has not been detected / identified in South Africa.

      Dr Sundar is a rust specialist, but do we know whether he worked on P. pachyrhizi?

      When Sundar visited South Africa, he had data available to confirm the species.

      During Dr Sundar's visit, he mentioned that P. pachyrhizi had been detected in South America but that it was not such a huge problem there.

      P. meibomiae is present in North and South America, while P. pachyrhizi is more an Asian rust. What you have, is two geographically separated rusts, that appear similar but are pathogenically very different. In Brazil it appears that there are two rusts that are difficult to separate when comparing the symptoms.

      Dr Kloppers mentioned that Dr Sundar had correctly identified the species. The South African isolate was compared with a Taiwan isolate, and both were confirmed to be P. pachyrhizi.

      If different types exist, can they be detected or can you only pick it up with differentials?

      PCR is very effective in differentiating between species.

      A lot of work still needs to be done to determine the different races?

      Yes, but one must differentiate between species and races.

      In the USA there was little concern about P. meibomiae, but concern about P. pachyrhizi is enormous. This implies that the species differ very significantly?

      The difference in pathogenicity is very substantial. The damage caused by P. meibomiae appears to be very limited.

      Should P. meibomiae spread to South Africa, what impact will it have and should methods for prevention be adopted or how should it be dealt with?

      Chemical control is the same for both species. The pathogens are not seed transmissible.

      Regarding the USDA conducting trials locally in cooperation with the University of Natal –  i) could the pathogens be introduced via the trial material,  ii) how will the trials be conducted and  iii under who's supervision?

      Only seed will be introduced, not spores for artificial inoculations. A 174 entry trial will be planted and data resulting from this will be compiled and handled by Dr Kloppers and his team. The entries from USDA are purely for cultivar testing and no disease will be introduced – no artificial inoculation will be done, only natural infection under South African conditions.

      Prof Laing mentioned that the meeting doesn't have to worry about the introduction of any new race – the billions of spores generated by infected soybeans, have generated so many new genes that millions of new races develop on a regular basis. He also stated that the testing of races and differentials are a waist of money. It is only an interesting academic exercise – new races develop everyday and depend on which cultivars are used (all cultivars are susceptible).

      Mr Scholtemeijer seconded Mr Vermaak's concern regarding the USDA trials and acknowledged Prof Laing's comment regarding money being spent unnecessarily, but despite all the new races being generated, the feeling is mutual that NO new disease is to be brought into the country.

      Dr Purchase asked that should anyone hear of a first report of rust in the USA, Ms Kruger must be notified so that the information can immediately be disseminated to all task team members.

      Does the disease follow a certain pattern with regard to air currents?

      The disease depends on the air currents. Spores have been found in air currents and jet streams and monitoring of air currents can give an indication of how the disease spreads. It can be assumed that the spread of rust from south to north America will be quick since there is a well established rust pathway based on air flows.

      The first SBR infection for the 2002 season was detected at Cedara and reported on 4 February 2002 (Ms du Preez), a month earlier than that of Mr Heinz Oellerman (1 March 2001). At the time of the Oellerman report, the disease had already spread substantially and had been detected in commercial fields. The disease spread very quickly around the Cedara / Howick area. It was then detected at Karkloof, Piet Retief and approximately three weeks later in Bergville and the cooler areas. The disease spread can be correlated with a physiological development stage – i.e. after flowering. The furthest point of infection was at Ermelo, although spread to the Highveld occurred at a very late stage (April 2002).

      The meeting noted that farmers generally sprayed very effectively (some farmers sprayed too early). Chemicals were extensively used and worked very well – i.e. helped to suppress the inoculum. Due to the relatively dry February / March, the conditions were not ideal for disease development. Under these circumstances, the disease was controlled fairly well.

      Prof Laing made the comment that despite the dry conditions in Natal, the disease was still severe. Dr Caldwell suggested that, based on greenhouse studies, temperature and humidity are a greater driving force behind SBR than physiological development stages.

      Mr Scholtemeijer expressed his concern regarding SBR detected in Ermelo and that Dr McLaren should make provision in his trials for indicator plots in Ermelo and the Highveld areas.

      Mr Lamprecht stated that this season attention will be give to detecting the disease on the Highveld.

      Ms du Preez asked that it be minuted that the disease was detected in the Umzimkulu area. She also indicated that the later plantings at Cedara were less severely infected and she ascribed this to the dry conditions experienced late in the season. Late plantings in Piet Retief were also less severely infected but this could not be attributed to dry conditions. Lower temperatures could have been a factor.

  7. Report back and discussion on planned research projects

    1. Fungicide trials – Ms ED du Preez

      See attachment 7.

    2. Soybean rust: risk analysis, loss assessment and quantification of the epidemiological value of in­ter­ven­tion technologies – Dr NW McLaren

      See Attachment 8.

    3. Hypothesis statement for breeding for soybean rust resistance – Mr AJ de Lange

      See attachment 9.

    4. Epidemiology trials at UNP – Dr PM Caldwell

      See attachment 10.

    5. Feedback from other research trials

      1. Mr L Killian

        See attachment 11.

      2. Mr A de Klerk

        See Attachment 12.

        Mr Scholtemeijer questioned the reduction in rates of Punch Xtra from the current emergency registration rate of 800 to 600 ml ha-1 as suggested by Mr De Klerk and the apparent contradictions of optimum rates and number of sprays between AVCASA, Cedara and Zimbabwean research results and asked for clarity on this point.

        Dr Laing explained that even though Zimbabwe has more experience in this field, South Africa has more pathologists doing trials on soybean rust which means that more results and answers can be obtained in a shorter period. He also commented that reduced rates are thought to reduce resistance development, but research has shown that reduced rates actually increase the rate at which resistance occurs.

        Dr Purchase commented that the single year trials done by AVCASA have been conducted for emergency registration purposes.

        Mr De Klerk explained that it is not strange for different companies to have different rates for the same disease – rate applications are mainly determined by the area and the climatic conditions.


        1. Major decisions are not to be made based on the results of single year trials.
        2. The trials are to continue as is and the results are to be compared with previous results before making and implementing decisions.
        3. Application rates to be placed on the agenda for the next meeting.
  8. General

    1. Strategy for coming season

      1. Fungicide trials (Ms Eve du Preez and Mr Neil van Rij)

        Status : Continue

        Suggestions / Resolution:

        1. Due to adjuvant trials in soybeans not being effective, different timing of adjuvant applications to be researched/tested.
        2. Trials to be conducted on ground application and with aerial applications – Mr Steyn (Monsanto) to be contacted regarding aerial applications.
      2. Risk analysis, loss assessment and quantification of the epidemiological value of intervention technologies (Dr NW McLaren)

        Status : Continue

        Suggestions / Resolution:

        1. Indicator crops in the Highveld to expand to include Bethlehem, Bethal, Ermelo. Mr Steyn suggested the Monsanto site at Bethlehem to be used as an indicator crop site. Mr Lamprecht to supply potential Bethal sites.
        2. Farmers to be made aware of the need to plant their own indicator crops.
        3. Assumptions of effect of row width, yield loss, physiological stage, time and fungicide application be based on more cultivars within a maturity group.
      3. Hypothesis statement for breeding for soybean rust resistance (Mr A de Lange)

        Status : Continue

        Suggestions / Resolution:

        1. A thorough evaluation of possible resistant sources to be conducted in order to do proper breeding.
        2. An internal GCI Workshop to take place in order to re-position personnel involved with the breeding process.
        3. Zimbabwe material showing sources of resistance to be followed up.


        Mr Scholtemeijer requested GCI to speed up the breeding process.

      4. Epidemiology trials at UNP (Dr P Caldwell)

        Status : Continue

        Suggestions / Resolution:

        1. Nutrient trial to be started.
        2. All epidemiology trials to be repeated.
        3. Mr Van Rij to develop a computer model.
        4. The microbiology trial to be finalised.
        5. Prof Pretorius to continue the differential trial.
      5. Other research trials

        1. Mr L Killian

          Status : Continue


          Cultivars be replaced with cultivars from different companies and that the cultivars be grouped / categorised according to maturity, in order to be able to make comparisons.


          1. Categorising according to maturity, to be placed on the agenda for the next meeting.

        2. Mr AJ Pretorius

          Status : Continue

          Suggestions / Resolution:

          1. All cultivar trials south of the escarpment and in Mpumalanga to be sprayed.
          2. Sprayed and unsprayed trials to continue and to be categorised according to cultivar maturity groups.
        3. AVCASA

          Status : Continue

          Suggestions / Resolution:

          1. Chemical companies will continue to conduct their trials as is for registration.
          2. Chemical companies must comply with the Registrar's standard.

          Dr De Kock agreed that the chemical companies continue with their trials as previously and requested that the results / information obtained be shared / published.


          Other chemical companies are to be invited to attend the SBR Task Team Meeting as AVCASA representatives.

          Mr De Klerk


          Consensus was reached that for the coming season, trials will be repeated, whereafter the trials can be adapted for subsequent seasons. This will enable researchers to effectively compare current results with new data.

    2. Control strategy

      See attachment 13, page 2.

      Control strategy Resolution
      Point 1 There is currently no other control strategy to follow, but to control the disease chemically with fungicides – to remain as it is. Approved (remain as is).
      Point 2 Chemicals that have been granted emergency registration are Punch C, Punch Xtra, Capitan 250EW, Folicur 250EW, Bayfidan 250DC, Shavit 25EC, Alto 100SL and Score 250EC. Ms Du Preez to supply the new emergency registrations (see Attach-ment 13). Alto 100SL to be taken off the pamphlet. Mr De Klerk suggested that the Registrar be contacted to confirm the entries / information, before altering the pamphlet.
      Point 3 Preventative spraying is far more effective than curative spraying and, if possible, is recommended especially and more specifically for the areas where the disease occurred in the previous season. This should however be subject to the confirmed presence of the disease in the area. Add-on: i) Farmers are advised to plant their own indicator crops, ii) indicator trials of the same cultivar to be planted 3 to 4 weeks prior to main plantings and iii) indicator trials to cover an area of ± 0.1 to 0.5 ha.
      Point 4 Regular monitoring of indicator crops and frequent radio and other media reports will provide information on the spread of the disease at district, provincial and national level. In this way soybean producers can be forewarned in order not to spray unnecessarily, but in time to control the disease prophylactic. Approved (remain as is).
      Point 5 Application rates and other relevant information is included in the label on the chemical containers and this should be read thoroughly and followed accordingly. Also consult reputable chemical companies and representatives for assistance. Approved (remain as is).
      Point 6 No varieties with genetic resistance are currently available. A number of companies and institutions are involved in breeding for resistance, but varieties with resistance will only be available in a few years time. Approved (remain as is).
      Contact names. Contact numbers to be added and existing list to be expanded.


      1. Maturity groups to be included in the pamphlet.


      Another year's data are needed to quantify the risk potential of maturity groups, before it can be added to the pamphlet

    3. Media strategy

      The committee was informed that an article containing an updated list of emergency registered fungicides for the control of soybean rust, has already been sent to the Farmer's Weekly for publishing (see attachment 14).

    4. SBR endemic or not?

      Consensus was reached that the disease is endemic east of the escarpment. We need to however, draw a line along the escarpment where, west of the escarpment, no artificial inoculation will be allowed, i.e. both in winter and in summer.

      The implications of the disease being endemic or not is to establish a protocol of guidelines for research and whether artificial inoculation in areas where the disease does not occur will create a source of infection to neighbouring commercial fields.

      Dr De Kock asked about the implications of the disease being recorded in Ermelo. It was suggested that we need to determine whether the disease has established itself in the area or whether it was a stray spore that blew in. Mr Scholtemeijer requested that any form of artificial inoculation in this area be postponed for another season. Selection under disease pressure will have to be done in areas where the disease occurs naturally. Prof Laing suggested that artificial inoculations during winter can be done at the University of Natal, Pietermaritzburg.


      Consensus was reached that west of the escarpment the disease is not endemic and that no artificial inoculation is to take place. If artificial inoculation is essential then use must be made of the Natal facilities.

    5. FAO funding from Rome

      Consensus was reached that west of the escarpment the disease is not endemic and that no artificial inoculation is to take place. If artificial inoculation is essential then use must be made of the Natal facilities.

      Suggestion / Resolution:

      1. University of Natal to try and obtain the mentioned letter from NDA.

        Dr Caldwell

      2. Letter from FAO to be forwarded to Mr Vermaak to enable GSA management to initiate communication with the Minister of Agriculture, in order to obtain the needed letter of support.

        Dr Purchase

  9. Date of next meeting

    The next meeting has been scheduled for Thursday, 24 July 2003 at the "NAMPO Park" in Bothaville. Registration to start at 08:30 with the meeting starting at 09:00.

  10. Adjournment

    The meeting adjourned at 15:00 after the Chairperson thanked everyone for their active participation in the discussions.