On Their Travels

A visit to St Lucia, West Indies
Windward Island Banana Development and Exporting Company

With the free weeks in summer 1996 between graduation and starting a Ph.D., I went to St Lucia to get some practical experience. I was met by Dr Ulrike Krauss at St Lucia's Hewanorra International Airport after an uneventful flight from London. The drive from the airport to the guest house, my home for the next nine weeks took us virtually the length of the island. It was immediately evident that St Lucia was lacking in flat land but definitely not in rain. In fact the island receives between 1500 and 3000 mm of rain per year depending on relief, not the 30,000 mm I saw stated on a sign in the rain forest. St Lucia is a tropical island paradise with rain forest covering the mountainous interior and agriculture covering the more accessible tracts of land. Bananas are the major agriculture product and are produced mainly on small holdings.

On the first full day on the island I spent reading up on banana crown rot disease, the most important of the post-harvest diseases. The following day I got to see the research station I had heard much about. This is the second laboratory Dr Krauss has had since coming to St Lucia three years ago. The first lab was washed out to sea during a tropical storm a couple of years ago; very little was recovered. Her present lab lacks an adequate electricity supply, which is a little frustrating as the lab is fitted with an air conditioning unit but the current is insufficient to run it. Consequently all sterile work was done first thing in the morning, before the fan was turned on and started to distribute spores and dust.

The work I got involved in was the screening of mycoparasites using a bioassay. This involved the production of hundreds of banana skin discs and inoculating with different combinations of pathogen and presumptive mycoparasite spores. After a few days the quantity of necrosis was assayed to determine the control offered by the mycoparasite. Some time was spent on looking at the mechanism of mycoparasitism microscopically. After cutting numerous samples for examination I was informed that I would make a good substitute for a microtone. A few field trials were undertaken while I was there. This generally meant me sitting cross-legged on the floor with several boxes of exceptionally rotten bananas and measuring the rot.

On a couple of harvest days we went out into the field. Banana production in St Lucia is markedly different to that of the central American dollar banana producers. There are 23,000 banana farmers on this island, which is approximately equal in size to the Isle of Wight. Some farmers have as little as half a acre. With farmers scattered over this mountainous isle and the infrastructure mediocre, the level of extension is low. This results in a variety of practices. In terms of crown-rot control the wrong fungicide is frequently used, and if the recommended one is used then the concentration is often questionable. Being out on extension exposes the difficult situation the farmer faces. A common reason for the wrong fungicide usage turned out to be the correct fungicide was not available. The greatest problem with crown- rot is that the farmer never sees it. Crown-rot, being a post-harvest disease, is not seen in the field, so a mental picture of it does not exist. Because it is not seen, it can easily be acquired and cost cutting practices can develop.

The island has more than just bananas and I did try and see more of the island, including the ?drive through volcano' which you can no longer drive through. An amusing time was being involved in a parrot survey. The St Lucian parrot is indigenous to the island and a survey of them was scheduled while I was there. We got early one morning to reach a good vantage point looking over the rain forest. This was all well before the 6 am sunrise. During dawn and dusk the parrots are most active. However, it rained during the whole survey period, we got drenched and the parrots stayed in bed: not a single one was spotted! I suppose being in a rain forest in the hurricane season, this was to be expected.

By spending nine weeks working with a specific disease I feel I have gained much. Things taught at college could at last be put into practice. While there I saw, in part, the specific problems facing a small island state with dependence on a single crop. In short I thank BSPP for partly financing this trip, which has aided in my training as a phytopa thologist.

Paul Matthews

Fusarium head scab: Global status and future prospects

Paul Nicholson and David Parry were fortunate to be invited to a truly international gathering of researchers interested in Fusarium ear blight, or head scab, at CIMMYT in Mexico City from 13-18 October 1996.

After the longest flight either of us had ever endured, we were whisked through to sprawling suburbs of Mexico City to the oasis of CIMMYT. What is more, we had to suffer the indignity of staying in a palatial Spanish- style mansion with its own swimming pool and tennis courts. Of course we were much too busy to take advantage of such extrava gances.

The primary reason for our meeting was the apparent increase in Fusarium ear blight in many cereal growing areas of the world. There were 22 invited delegates from 17 countries together with another dozen or so resident CIMMYT personnel and we were trying to exchange ideas and build up a global picture of the significance of the disease and improve our methods of control.

Most delegates were associated in some way with breeding for resistance, although there were several mycotoxin experts and a few presentations concerning fungicides. We were obviously deemed to be an important group as the introductions included a statement by the director of CIMMYT, Prof. T.G. Reeves and the Austrian Ambassador, Dr Kurt Henkel. Why the Austrian Ambassa dor you may well ask. The original concept for the meeting was developed by Prof Peter Ruckenbauer who is the Director of the Institute of Crop Production & Plant Breeding at the University of Vienna, and he and his colleagues, together with Dr Jesse Dubin and Lucy Gilchrist at CIMMYT, were responsible for organising the meeting. At all times Jesse, Lucy and the rest of the well oiled CIMMYT machine ensured the smooth running of the meeting and attended to the various needs of the participants.

Resistance breeding & mycotoxins

The first morning consisted of a series of presentations by Ruth Dill-Macky (University of Minnesota), Lucy Gilchrist (CIMMYT, Mexico City), Martha Diaz (INIA, Uruguay), and Maria Theresa Galich (INTA, Argentina) as an overview of specific breeding pro grammes in contrasting locations. We then moved on to the first talk on the importance of mycotoxins by Anne Desjardins who reported some very interesting research on mutants of Fusarium species which lacked the gene responsible for mycotoxin synthesis. Bob Bowden from Kansas State University followed on with sexuality and diversity in Gibberella zeae and Paul finished this session with some of his work on the development and application of quantitative PCR to Fusarium ear blight.

The next, large session was on screening and breeding progammes in a range of countries. Jeannie Gilbert (Canada), Hermann Buerstmayr (Austria), Peidu Chen (China), Jackie Rudd (South Dakota), Tomohiro Ban (Japan), Akos Mesterhazy (Hungary), Ravi Singh (Mexico), Irina Ablova (Russia), and Radshey Pandeya (Canada) all related their progress in searching for resistance sources and trying to achieve the most appropriate techniques for inoculation. I was quite surprised about the degree of consistency in both these areas. Frontana and Sumai 3 kept coming up as the most promising, and best studied sources of resistance to the disease.

Much debate centred around disease screening methods but the consensus was that spray inoculation of conidia at anthesis and point inoculation of spikelets at a similar growth stage were the best methods to assess resistance to initial infection and colonisation (Type 1 and Type 2 resistance respectively). Elena Klechkovskaya from the Ukraine then presented a paper on control and this was followed by a review of the signifiance and control of the disease by David.

The following day we were up early and onto a coach bound for the CIMMYT field station at Toluca, a mere 2800m above sea level and famous as the source of the A2 mating type of Phytophthora infestans. After a quiet trip through Mexico City during rush hour (they are such careful and courteous drivers) we arrived at the relatively cool but sunny field station and were shown the nurseries for wheat breeding. This was followed by lunch consisting of huge barbequed cow sides washed down with beer. An enjoyable field trip if ever there was one!

International collaboration

The next day, after hearing more about mycotoxins from Akos Mesterhazy (Hungary) and Maya Pinero (Uruguay) were were asked to assemble in the board room and sit in countries, a bit like the United Nations, to draw up a collaborative research proposal (fight over funds). This actually turned out to be a good natured affair and we did indeed get some reasonable ideas down relating to our priorities. for funding. The main emphasis was the need to find and incorporate sources of resistance to the disease in well adapted wheat cultivars, but we also recognised the need to integrate resistance varieties in a strategy for control which included fungicides where these were available. The proposal will be put to CIMMYT for funding by donor governments.

I think we both learned a lot from this meeting, particularly relating to the interna tional significance of the disease. Time after time speakers would start their talks with some sort of significance statements. For example the Canadian delegate started his paper by stating that in their region this year they had just lost $1 billion as the result of yield losses and mycotoxin contamination of wheat. I also think we realised how fortunate we were working in the UK despite our research funding problems. The Ukrainian delegate had not been paid for 6 months and she was not sure whether she would have a job at all upon her return.

Both of us had some time after the meeting for a little sight seeing and were astonished at the geographical and cultural diversity which exists in Mexico. Seeing ethnic Indians worshipping the sun on top of the 3000 old sun pyramid on a Sunday morning was a mild contrast to morning prayer in our local Anglican church (David).

We would like to thank the organisers and all those involved in the meeting for their invitation to attend and their hospitality. We would also like to thank the British Society for Plant Pathology most sincerely for their contribution towards the cost of this trip.

David Parry

Harper Adams Agricultural College, Newport, Shropshire

Paul Nicholson

John Innes Centre, Norwich

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