In order to evaluate the improvement of rubber productivity of rubber trees by late upward tapping. A study was conducted at SCASO (Société Civile Agricole du Sud-Ouest) on the PB 260 clone of the active metabolic class. The experimental set-up is a Fisher block design with eight treatments and three replications. The treatments compared were bled in reverse in the eleventh year of harvest, in quarter spiral every 3, 4, 5 and 6 days, with stimulation frequencies of 6, 8, 10, 12 and 13 times a year. The parameters measured were rubber production, isodiametric growth, sensitivity to dry notching of trees and physiological profile. The results show that the different latex harvesting technologies improve the rubber productivity of PB 260 (5469 kg.ha-1.yr-1) with a low dry-nut rate (1.2%) and satisfactory radial vegetative growth (3.9cm.yr-1). The physiological profile of the trees is balanced, but the treatments significantly influenced the different parameters except sucrose. Trees bled in S/4U d3 gave better results due to their high yield with an acceptable dry notch rate. Late reverse tapping is therefore a good latex harvesting technology for improving rubber productivity after down tapping.

Tapping panel dryness is an important limiting factor in rubber productivity of Hevea brasiliensis. In order to assess the sensitivity to this syndrome, the effect of two intensive latex harvesting technologies on moderately metabolized GT1 clone, has been studied in the South-Eastern region of Côte d'Ivoire. The rubber trees were planted according to the experimental mono-tree device, "One tree one plot design" a tree constituting a repetition, and 31 trees per treatment, selected on circumference and health status criteria. The parameters measured were rubber production, circumference increase, physiological profile and tapping panel dryness sensitivity. The results showed that induction of tapping panel dryness in latex harvesting system, S/2 d/3 6d/7 ET 10 % Pa 1 (1) 1/ w) was significantly low (0.18 ± 0,22 %) than that of the control (S d/1 6d/7 unstimulated, 1.43 ± 1.45 %). Productivity of this particular system was also good (62 ± 16.32 g.a-1.s-1) and it especially has less stress that can cause physiological fatigue, or even the notch dry. Otherwise, Rubber production, radial vegetative growth, physiological parameters of the latex and the tapping panel dryness rate were influenced by the two treatments applied to GT 1. In addition, the medium and high sucrose contents (16.5 ± 3.01%) and thiol group (0.51 ± 0.13 mmol.l-1) of the latex in the treatment (S/2 d/3 6d/7 ET 10% Pa 1 (1) 1 / w), were instrumental in the response to this stimulation. The sensitivity to the tapping panel dryness is in very close linear relation with the harvest intensity of the latex to which the GT 1 clone has been subjected. These results corroborate and confirm the moderate sensitivity to the tapping panel dryness of GT 1 clone.

Improving the productivity of rubber trees has always been a major concern for rubber farmers. The majority of growers opt for overexploitation of the trees. This disturbs the physiological balance of the rubber trees, which leads to the recrudescence of tapping panel dryness and rather to a drop in production. To solve this problem, the present study proposes to define a latex harvesting technology (or technologies) for the moderate metabolism clone class that will allow the improvement of plantation yield and the increase of the economic life of the trees. To achieve this, the GT 1, RRIC 100 and BPM 24 clones of the moderate metabolism class were used as plant material. The results showed that the reduction in tapping frequency had no negative effect on the vegetative state of the trees. This reduction was compensated by a high number of annual stimulations, which resulted in high dry rubber production. Analysis of dry rubber production, radial rubber growth and tapping panel dryness rate indicates that the moderate metabolic class clones performed better with the latex harvesting technologies S/2 d3 6d/7 ET2.5% Pa1(1) 6/y; S/2 d4 6d/7 ET2.5% Pa1(1) 6/y and S/2 d5 6d/7 ET2.5% Pa1(1) 1.

Aims: Banana and plantain contribute to food security in Côte d'Ivoire. However, one of the major difficulties arising in its production remains parasitic constraints causing the loss of production. Among these constraints, leaf diseases cause more damage. Methodology: This study was initiated to analyse the nature of host-pathogen interactions (resistance or sensitivity) between the fungus Deightoniella torulosa and certain varieties of banana and plantain in Côte d'Ivoire. The pathogenicity of the fungus was measured from artificial inoculation on leaf fragments that were kept alive on a specific culture medium in Petri dishes. This medium consisted of agar amended with Benzimidazole. Leaf’ fragments that survived inoculation of spore suspensions, exhibited the characteristic symptoms of the fungus Deightoniella torulosa. The impact of the fungus on the degradation of chlorophyll was noted. Results: The results showed that the strains of Deightoniella torulosa have a pathogenic activity on the banana trees. The concentration of 75 μM of Benzimidazole incorporated into the survival medium can be used for inoculation tests on leaf fragments. Conclusion: The Grande Naine cultivar could be used as a control indicator for D. torulosa.

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