Parasitical Fungi in Cashew (Anacardium occidentale L.) Orchard of Cote d`Ivoire

Abstract

Background and Objective: Cashew tree (Anacardium occidentale L.) is an important fruit tree mainly culture for the edible nuts providing substantial income to farmers in northern and central regions of Côte d’Ivoire. However, the productivity is threatened by the strategies development and extension of diseases. Therefore, this study aimed to identify pathogens involved in cashew diseases. Materials and Methods: Leaf, shoot tip, twig, flower and fruit samples were collected in the most important cashew-growing areas of Côte d’Ivoire. Sections of 4-6 mm diameter from the periphery of lesions where surface sterilized in 70% ethanol and then in 3% sodium hypochlorite followed by abundant rinsing in sterile distilled water. After removing excess of water, fragments were placed on PDA medium. Symptoms associated with the pathogens in the field were described. To test the pathogenicity of isolates obtained, leaves of twenty eight days seedlings were sprayed with a spore concentration of 106 mLG1 used as inoculum for each isolate. Data collected were analyzed using analysis of variance (ANOVA 1) with Statistica version 7.1 software. Results: The results revealed that the different pathogenic diseases of cashew in Côte d’Ivoire are caused by Colletotrichum gloeosporioides (63.45%), Pestalotia heterocornis (30.35%), Lasiodiplodia theobromae (1.66%) and other unidentified pathogens. Pathogenicity of isolates was verified by the implementation of Koch’s postulate. Conclusion: This study confirmed the presence of pathogenic fungi on cashew and the fact that some of these fungi can induce symptoms reducing leaf photosynthetic area and the production capacity. Based on pathogenic characterization of fungi, strategies need to be developed in order to identify fungi species and integrated disease management approaches.