Centre National de Recherche Agronomique

Background: Food self-sufficiency is a real challenge for Côte d'Ivoire today, with national decreasing of rice production for population's needs. This production deficit is attributed not only to the use of unsuitable and unproductive varieties, but also and above all to the infertility of rice-growing land. Aims: This study aims to improve rice production in Vavoua through the use of organic fertilisation in a context of sustainable organic farming. Place and Duration of Study: The experiment was conducted in the field in 2024 in the village of Mignoré, in the sub-prefecture of Séitifia and in the department of Vavoua, in central-western Côte d'Ivoire, by the agropedology research team at Jean Lorougnon Guédé University in Daloa, Côte d'Ivoire. Methodology: three formulations (C1, C2 and C3) of composts were developed based on coffee husks and rice straw in different proportions. The formulations were for compost C1 (100% rice straw), C2 (50% rice straw + 50% coffee husks) and C3 (100% coffee husks). These different composts were applied as an organic amendment at a rate of 40 t/ha to two varieties of local rainfed rice, “Akadi” and the improved “C26”, in two applications (basal and top dressing) in a randomised Fisher block design with three replicates. The parameters collected were height, number of tillers, number of panicles and yield. Results: the experiment showed that C2 compost had the best physicochemical characteristics compared to the other two and most improved the agronomic performance of the rice. The C26 rice variety stood out by achieving the highest yield. Conclusion: C2 compost in the formulation (50% coffee husks and 50% rice straw) can be recommended as a good substitute for mineral fertilisers in the ecosystem of our study.

Pseudotheraptus devastans (Heteroptera: Coreidae), commonly known as the coconut bug, is a major pest of coconut palms in Côte d'Ivoire. All larval stages and adults cause damage by their bites, resulting in either deformation of young nuts or their fall. As part of the search for a strategy to protect these nuts from attack, an evaluation of the effectiveness of essential oils from Allium sativum and Allium cepa was tested on out. The study was conducted at the coconut research station of the National Centre for Agricultural Research in Côte d'Ivoire. The essential oils extracted from the two aromatic plants were tested by contact using a hand sprayer at different concentrations on the eggs, larvae and adults of P. devastans at a temperature of 26.39 ± 1.50°C and a relative humidity of 87.85 ± 2.15%. These essential oils have insecticidal properties against P. devastans. The essential oil of A. sativum had LC (50) and LC (90) values of 0.27 ± 0.6% ; 11.24 ± 0.57% for larvae and 3.82 ± 0.07% ; 11.28 ± 0.17% for adults, whereas that of A. cepa had LC (50) and LC (90) values of 0.59 ± 0.51% ; 38.16 ± 0.93% for larvae and 4.84 ± 0.10% ; 20.05 ± 0.25% for adults. The essential oil of A. sativum was therefore the most toxic.

Growing pepper trees (Piper nigrum) face several production constraints. The objective of this study is to identify the cutting techniques that allow better development of pepper crops in the nursery. Three clones (C1, C2, and S) were used for this study. These clones were cut in four locations (under tunnel, under shade, closed bin, and open bin) following a two-factor split-plot design. Six agro-morphological parameters relating to the growth of the vine were collected on plants. They are mortality rate, number of leaves, leaf length, leaf width, leaf surface, length of vines, and number of vine leaves. The results of this study showed that the open bin had the lowest mortality rate in the nursery (26%). Clone S, a wild species, obtained mortality rates of 4 to 5% respectively in the closed and open bins. In addition, the closed bin produced the longest vines (30.32 cm) and with the highest number (8.46) of leaves per vine. Moreover, the leaves of plants in this environment obtained on average the greatest length, width, and leaf area, respectively 9.82 cm, 5.59 cm, and 45.42 cm². These results constitute an indicator for breeders in the perspective of large-scale diffusion of pepper to farmers. Key words: Cutting, improvement, Ivory Coast, pepper.

In sub-Saharan Africa, the bark of Vitellaria paradoxa C.F. Gaertn (Sapotaceae), commonly known as Karité, is used in the treatment of many skin and digestive ailments. In order to justify this traditional use, the present study was undertaken to evaluate the method of preparation, the antifungal activity, the chemical composition and the acute toxicity of the bark of Vitellaria paradoxa on Candida albicans. Total aqueous (LeA) and 70% ethanolic (LeE) extracts of the bark of Vitellaria paradoxa were prepared and tested in vitro. Ethanolic extract (LeE) showed the highest yield (55.5%) and was found to be more effective on the growth of Candida albicans with a minimum fungicidal concentration (CMF) value of 1.56 ± 0.02 mg / ml and a 50% inhibitory concentration (IC50) of 0.39 ± 0.21 mg / ml, certainly justifying the use of the plant in traditional medicine. At the end of the acute toxicity assessment test, the LD50 was estimated to be greater than 2000 mg / Kg orally. The phytochemical screening of the various extracts showed the presence of chemical compounds which justify their antifungal activities by the use of Vitellaria paradoxa. This work has provided a scientific basis for the use of Vitellaria paradoxa in traditional pharmacopoeia, particularly in the treatment of fungal pathologies.

Swollen shoot is a viral disease of the cocoa tree in the major cocoaproducing areas of West Africa. Its progression can be influenced by several factors, including climate and soil. This study aims to assess the impact of mealybug vectors, climate and soil on the spread of swollen shoot disease in order to develop more effective control methods. It was done in the counties of Abengourou, Bouaflé, Divo and Soubré. Three plots showing early signs of infection were selected in each department. Thus, 6 concentric lines from a disease foci in different directions were defined and each line includes 9 unaffected cocoa trees. These cocoa trees were tracked for 2 years. The data collection consisted of determining the number of diseased and dead trees as well as the number of colonies of mealybug species on each tagged cocoa plant. In addition, composite samples were taken in the 0–60 cm stratum of each plot to determine the texture, composition of organic matter and soil chemicals. Then, climate data, including rainfall and temperature, were collected over the observation period. The variance analysis indicated homogeneity between the dry and wet seasons, between clay-silt and claysandy soils, and between soils low in organic matter and those with acceptable organic matter, in terms of disease effects and mealybug populations. However, in the dry season, the Pearson correlation was significant between these variables in the departments. Thus, it was also significant between the level of sand, potassium (K+), magnesium (Mg2+), and exchangeable phosphorus contents, and the pH according to the textures studied and the soils poor in organic matter. Water deficit, texture, organic matter and nutrients of the cocoa tree are the factors that impact the spread of swollen shoot disease. These factors can therefore be used to implement an effective measure to combat swollen shoot disease.

Vermicomposts and vermiwashs obtained from pre-composted cassava peelings (Ca.Pe), cocoa shells (Co.Sh) and cashew nut shells (Ca.Nu) were assessed for physical characteristics and nutrients content. Five types of substrates were made from cassava (VC1), cashew (VC2), cassava and cashew (VC3), cassava and cocoa (VC4), cocoa and cashew (VC5). About 45 kg of each pre-compost was then placed in a plastic compost bin to be digested by 600 g of earthworms (Eudrilus eugeniae) for 11 weeks. The biofertilizers obtained were analyzed for their total organic carbon, macronutrients and micronutrients content. The pH of the different types of vermicomposts (VC) varied from 5.8 to 8.15. NPK levels varied and depended on the type of substrates used for vermicomposting. Highest values were found in vermicompost from mixed substrates. VC5(18.01; 3.89 and 18.7g/kg), VC4(20.99; 1.29 and 13.7g/kg) and VC3(17.91; 0.91 and 8.72g/kg), VC2(18.06; 0.39 and 4.64g/kg) and VC1(21.19; 0.34 and 2.25g/kg. The pH of the vermiwashs (VW) was alkaline (7.65 to 9.25) and their NPK content was lower than that of the VCs: VW1 (2.09; 0.08 and 2.18g/L), VW2(0.49; 0.09 and 0.44g/L), VW3 (0.33; 0.12 and 1.05g/L), VW4 (2.18; 0.18 and 2.50g/L) and VW5 (0.27; 0.18 and 1.99g/L).

Garcinia kola, a high-socioeconomic and multipurpose fruit tree, has been shown to have a low germination and long juvenile phase, which limit its cultivation initiative. Our study aimed to determine successful G. kola grafting conditions to promote its cultivation. So trials were carried out in June and August, testing four grafting methods: simple whip, top cleft, side cleft, and chip budding made on 12- and 36-month-old rootstock. The grafts were unwrapped at 15, 22, and 29 days after grafting. The results showed that the month of June is the favorable period for G. kola grafting. The best grafting success was observed with the chip budding and top cleft grafting methods applied on the 36- and 12-month-old rootstocks, respectively. The graft unwrapping time at 29 days after grafting promotes the best grafting success. The combined effect showed that the best graft success rate was recorded in June on 36-month-old rootstock (43.33%) with the chip budding and side cleft grafting method and 83.33% for the graft made on 12-month-old rootstock with the top cleft grafting method, respectively. This study is an important step for good plant material for domestication and cultivation of this resource.

Africa boasts high biodiversity while also being home to some of the largest and fastest-growing human populations. Although the current environmental footprint of Africa is low compared to other continents, the population of Africa is estimated at around 1.5 billion inhabitants, representing nearly 18% of the world's total population. Consequently, Africa's rich biodiversity is under threat, yet only 19% of the landscape and 17% of the seascape are under any form of protection. To effectively address this issue and align with the Convention on Biological Diversity's ambitious '30 by 30' goal, which seeks to protect 30% of the world's land and oceans by 2030, substantial funding and conservation measures are urgently required. In response to this critical challenge, as scientists and conservationists working in Africa, we propose five recommendations for future directions aimed at enhancing biodiversity conservation for the betterment of African society: (i) accelerate data collection, data sharing and analytics for informed policy and decision-making; (ii) innovate education and capacity building for future generations; (iii) enhance and expand protected areas, ecological networks and foundational legal frameworks; (iv) unlock creative funding channels for cutting-edge conservation initiatives; and (v) integrate indigenous and local knowledge into forward-thinking conservation strategies. By implementing these recommendations, we believe Africa can make significant strides towards preserving its unique biodiversity, while fostering a healthier society, and contributing to global conservation efforts.This article is part of the discussion meeting issue 'Bending the curve towards nature recovery: building on Georgina Mace's legacy for a biodiverse future'.

ABSTRACT Cabbage (Brassica oleracea L.) is a plant of vital importance. However, its cultivation is subject to several diseases, including Alternaria leaf spot, which causes huge losses in most production areas. Thus, the present study aimed to identify the Alternaria species responsible for Alternaria leaf spot of cabbage in Côte d’Ivoire. To this end, a phytosanitary survey was carried out in three cabbage growing areas in Côte d’Ivoire (Yamoussoukro, Tiassalé and Abengourou), and symptomatic leaves were sampled. The fungi associated with the symptoms were then isolated and morphologically identified. Pathogenicity tests were also carried out with Alternaria isolates by inoculating cabbage plants in a greenhouse. Finally, pathogenic Alternaria isolates were molecularly identified using the universal primers ITS1 and ITS4. Alternaria leaf spot symptoms were found in all three locations surveyed. Disease prevalence ranged from 63.33% to 78.33%. As for symptom severity index, it was highest in Abengourou: 43.61%. Five Alternaria morphotypes were isolated from the collected samples. These isolates were all pathogenic to cabbage, and molecular tests revealed that they belonged to the species Alternaria brassicicola. This first identification of Alternaria brassicicola as a cabbage pathogen in Côte d’Ivoire will thus contribute to the implementation of an effective control strategy against Alternaria leaf spot of cabbage.