The rubber tree, Hevea brasiliensis, is cultivated in many humid tropical countries for the latex it produces, from which is extracted natural rubber mainly used by the tyre industry. Asia alone provides almost 95 % of the world production, where the first producer is Thailand whose rubber industry earns a regular income for 10 % of the population. However, a disease is attacking rubber trees that causes irreversible drying-up of latex flow, and can affect up to 30% of trees in African, Asian and American plantations, causing marked falls in production and substantial economic losses. Termed “rubber tree bark necrosis syndrome” (RTBN), it was diagnosed in 1983 (4) in an industrial-scale plantation estate (Michelin company, Ivory Coast) by IRD researchers. The first investigations, conducted at the request of the plantation company, could not establish a link between RTBN and any pathogenic agent (fungus, virus, bacterium or mycoplasm).
Further research projects were launched at the end of 1999 by the IRD team and its partners (2) at the request of the rubber production sector and with its support (1). This complex syndrome was then tackled using a multidisciplinary approach (involving plant pathology, agricultural soil science, cell and molecular physiology, virology, and so on) and focusing on several different localities (3), which provided conditions for identifying its origin and activating mechanism.
Since the 1970s, the predominant basis of rubber cultivation has been propagation by grafting on tree stock. In 90% of cases, RTBN attacks the tree vascular tissues, starting right at the grafting point situated in the transition zone between the trunk and the roots, the collar. The first stage of the disease is not detectable because the first cells to undergo necrosis are located in internal tissues of the bark. The necrosis, however, extends steadily to the whole base of the trunk before travelling upwards, up to the tapping notch. At this stage, the notch no longer produces latex and the affected trees are then noticeable. When the outer bark becomes diseased, cracks begin to appear starting from it and then dead parts flake off.
Marie Guillaume | alfa
Riding a horse is far more complex than riding simulators
04.08.2015 | Veterinärmedizinische Universität Wien
Tropical deforestation releases large amounts of soil carbon
28.07.2015 | Georg-August-Universität Göttingen
Continuing current carbon dioxide (CO2) emission trends throughout this century and beyond would leave a legacy of heat and acidity in the deep ocean. These...
Glacier decline in the first decade of the 21st century has reached a historical record, since the onset of direct observations. Glacier melt is a global phenomenon and will continue even without further climate change. This is shown in the latest study by the World Glacier Monitoring Service under the lead of the University of Zurich, Switzerland.
The World Glacier Monitoring Service, domiciled at the University of Zurich, has compiled worldwide data on glacier changes for more than 120 years. Together...
Using ultracold atoms trapped in light crystals, scientists from the MPQ, LMU, and the Weizmann Institute observe a novel state of matter that never thermalizes.
What happens if one mixes cold and hot water? After some initial dynamics, one is left with lukewarm water—the system has thermalized to a new thermal...
Physicists from Regensburg and Marburg, Germany have succeeded in taking a slow-motion movie of speeding electrons in a solid driven by a strong light wave. In the process, they have unraveled a novel quantum phenomenon, which will be reported in the forthcoming edition of Nature.
The advent of ever faster electronics featuring clock rates up to the multiple-gigahertz range has revolutionized our day-to-day life. Researchers and...
Researchers have developed an ultrafast light-emitting device that can flip on and off 90 billion times a second and could form the basis of optical computing.
04.08.2015 | Event News
23.07.2015 | Event News
10.07.2015 | Event News
05.08.2015 | Business and Finance
05.08.2015 | Social Sciences
04.08.2015 | Information Technology