PANEL TAPPING MANAGEMENT AND TRUNK PHLOEM NECROSIS OF RUBBER TREE (Hevea brasiliensis) IN IVORY COAST

The global objective of this study is to identify the agricultural techniques minimizing bark necrosis at Hevea brasiliensis. In a specific way, it is to find out the tapping panel the management technique which minimizes bark necrosis on six clones of rubber tree (IRCA 111, IRCA 109, IRCA 130, IRCA 18, GT 1, PR 107) in the southwest of Ivory Coast. To achieve these goals, the observations related to the number of trees attacked by bark necrosis and tapping panel dryness were made through the complete statement and the dry panel statement. The taking into account of tapping panel dryness in this study is justified by the fact that it may be related to bark necrosis. The importance of bark necrosis and the tapping panel dryness on the clones was checked respectively by the rate of necrosis and the length of the diseased tapping panel cut. It appeared at the end of this study that the management of tapping panels does not influence the development of bark necrosis and tapping panel dryness on the clones of Hevea brasiliensis under the d/4 6d/7 conditions of exploitation with modes of stimulation specific to each clone. This agricultural technique which was until suspected to amplify bark necrosis did not show any link with the disease. Indeed the clonal factor influences the rates of the disease. All the clones expressed both diseases, but at different levels. Some clones were shown less tolerant (IRCA 130) or tolerant (GT1) at the same time to both diseases. Tapping panel dryness and bark necrosis do not appear here according to the metabolism of the clones (active, intermediate or slow).