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The heart of the matter: Phytophthora devastation of oil palm in South America and the 17th International Oil Palm Conference, Cartagena, Colombia September 2012
Late September 2012 saw me in the remarkable walled (to counter Sir Francis Drake’s piratic assaults) coastal town of Cartagena in Colombia as an invited guest of the XVII International Oil Palm Conference. This was organised by FEDEPALMA, the national arm for Colombian oil palm growers and trade and by CENIPALMA, the research arm. I have long worked on the two major diseases of oil palm in Africa (Fusarium wilt) and in South East Asia (Ganoderma basal stem rot). South America has its own disease problems and one, known perhaps incorrectly as bud rot, is devastating some areas. The temptation for me was therefore to combine this conference with a field visit organised by the Malaysian Palm Oil Board (MPOB) in order to get a close look at the disease, talk with the local scientists and try to judge risks to other regions, in particular SE Asia. Malaysia and Indonesia produce c. 86% of world palm oil production and overall palm oil makes up almost 40% of the world’s vegetable oil. Oil palm has been a controversial crop, but is increasingly grown sustainably (see www. rspo. org), its output greatly exceeds that of annual crops, and as a perennial tree, it performs well in terms of carbon capture.
At the conference the Director General of MPOB Dr Choo Yuen May described how early plantings in the 1970s often involved environmental transgressions, such as forest clearing, burning and river pollution, but now current practices are sustainability driven and Malaysia will retain 56% of its forests. The conference had numerous trade exhibitors many of whom were concerned with efficient processing and the environment, such as using residues from mills as renewable energy or as fertilizers, or trapping biogas from mills.
The conference offered pre-meeting field visits to estates, mills and a biodiesel plant. The relevant sessions of interest to BSPP readers were beautifully named “Integrated management of plagues and diseases”. Plagues aside, I will mention Ganoderma and Fusarium, which two of us described, but I will focus here on the cause and effect of “bud rot”. Translated in Spanish that is Pudricion de Cogolla (PC) or in Brazil Amerelacimento Fatal (AF) or fatal yellowing.
There are many confusing names referring to types of spear rot and bud rot, often with no pathogen identified. The Colombian version at least develops in the palm heart (cogollo) above the meristematic zone on immature spear leaves. Ultimately the necrosis can extend to and kill the meristem and whole palm. Bear in mind that each palm yields for typically c. 25 years so the loss of each palm is truly considerable. The diverse names may well reflect different causes, but at long last after a mere 40 years or so, a recent paper (Torres et al. (2010) Plant Disease 94, 1163) describes the causal agent as Phytophthora palmivorum.
Certainly that is what Cenipalma believe and are researching and what the two conference speakers from Australia, Andre Drenth (U Queensland) and David Guest (U Sydney) described. Guest gave excellent accounts (including a really well made movie) of successes of largely cultural control of P. palmivora in other tropical tree crops such as jackfruit, using a combination of good nursery practice, mulching, drainage, hygiene (removal of affected fruits), and phosphonate application as a defence inducer. He emphasized the value of grower participation and “ownership”.
The smallholders appeared very happy as a result. I will return to the disease and its control later.
There is every chance that Phytophthora will be attributed as the cause of all these related syndromes on oil palm and that might be dangerous. There is much more in depth pathology research needs yet to be done on this major world crop.
After the meeting the so called “Bud Rot Task Force” flew up to the cooler climes of lofty Bogota to discuss background and strategy, and to visit FEDEPALMA HQ. The reduced oxygen level caused a few of us sleep problems and a brief earthquake of grade 7. 3 no less, upset the MPOB Director General who was on an upper floor of the hotel, whilst those of us having a brief tour of old Bogota (buying emeralds for our loved ones. . ) were unaware. The task force comprised MPOB representatives, colleagues from two of the major Malaysian companies (FELDA and Sime Darby, with whom I often collaborate) and my colleague from our early work at Bath on Fusarium of oil palm, Julie Flood from CABI. Also we were joined by a major Colombian grower and trader in palm oil of two generations.
We were to visit the badly affected Pacific west coast around Tumaco but security issues (yes they still exist in some areas) diverted us to the low, hot Magdalena valley and Barrancamerjeba.
This is the oil (fossil oil) capital of Colombia as evidenced by ubiquitous nodding donkeys and pipelines, but an attractive, verdant area nonetheless.
We visited Cenepalma’s well provided labs in a fine forest setting, where a committed and hospitable Dr Gerardo Martinez and his enthusiastic young team are isolating and inoculating Phytophthora.
Fruit baits were especially effective for pathogen isolation. Zoospore inoculations of immature spear leaves (where the disease takes hold) of seedling palms seemed to some of us to result in very limited lesions looking almost like a resistant reaction. However zoospores on very young, almost white unopened spears did cause spreading water-soaked lesions. I encouraged them to reduce inoculum level as a concentration series, because a simultaneous challenge with 20,000 spores is unlikely to occur in a field situation.
They are also working with Ganoderma, which is less of a problem but still a concern in view of the ever increasing damage inflicted by this disease in SE Asia.
The subsequent field visit, which included the grower Jorge Corredor who has personally lost 3200 ha to the disease mainly in the coastal Pacific area, revealed the scale of devastation and the complexity of the disease. It may be that secondary colonizers cause much of the damage and insect vectors are involved to get the inoculum deep into the growing point. My images tell their own story of the seriousness of the situation.
The scene recalled to me my visit to Para State Brazil in 2011 with EMBRAPA.
There again I witnessed large areas of similar devastation, but on that visit the cause (of AF) was claimed to be unknown.
In Colombia, clearly rainfall and drainage play a key role, which fits with the nature of Phytophthora. In areas with dry seasons, such as the savannah, disease recovery occurs, albeit temporary.
The wet west coast has been devastated by 85% with 300 of 350k ha destroyed between 2006 and 2009. The central area between the Andes had marked seasons but after the last three years of El Nino-induced wet, bud rot is very severe and moving rapidly, as we witnessed.
The Malaysians were there of course for biosecurity issues fearing potential disease spread. However, P. palmivora has long been present there, for example on cocoa, jackfruit and durian, in some cases adjacent to oil palm plantations.
Why is the disease not expressing in Malaysia? There was general consensus that better water and nursery management in Malaysia probably play a key part. It is not that the palm lines grown there are resistant, because they succumbed when planted in Colombia. It remains to compare the aggressiveness of isolates from the two regions (and here, getting the zoospore numbers right to create an appropriate may be crucial). In this context I heard from one UK colleague that a sequencing project had revealed major differences between a Colombian and an Indonesian isolate. CENIPALMA need to be much more aware of the great variability and flexibility that Phytophthora can exhibit. It is feasible that the Colombian strains co-evolved with the many native palms in the forests. Also in some regions the South American oil palm Elaeis oleifera is endemic. The commercial palm E. guineensis introduced from Africa has proved to be completely susceptible, whereas E. oleifera can show some tolerance or resistance. The only currently successful strategy is to use the O x G hybrid, which usually resists bud rot very well (likewise it is used successfully against AF in Brazil). The hybrid has its problem in terms of assisted pollination and oil yield but for now is the only option. Screening E. guineensis crosses for bud rot resistance is clearly required, as has been performed long-term and with considerable success for Fusarium and is being currently undertaken for Ganoderma; these approaches have been published by us and others and were well described by Tristan Durand-Gasselin at the Cartagena meeting.
Next time I would hope to visit Cartagena and surrounding areas with time to spare as there is great history, colonial architecture, ancient cultures and ecological diversity to be enjoyed. Indeed this applies to much of the enormously diverse country of Colombia; just ensure you first check up on those few areas to avoid. One road block, off-piste towards Magdalena valley (luckily it was the army with no doubt reliable 16 year olds and their trusty automatic weapons) made me realise how much Julie Flood and I stood out as potential kidnapees; and I’d forgotten my essentialto- carry-at-all-times passport. My adrenalin level has returned to normal, rest assured.
I wish to thank BSPP for helping me to fund this challenging and fascinating visit.
Richard M. Cooper University of Bath