Inventory and spatial distribution of some cashew trees (Anacardium occidentale L) diseases (Anthracnose and Gummosis) in Mali

Abstract

The cashew tree (Anacardium occidentale L.) is one of the world's leading export crops,and West Africa holds the top spot, with Côte d' Ivoire producing 2.33 million tons of cashew nuts annually over 4.7 million hectares. Despite its importance, cashew production faces biotic and abiotic constraints. The objective was to contribute to the protection and improvement of cashew plantation production in Mali. Ten locations including each six orchards were surveyed. Samples were collected from several plant organs' symptomatic sections. To map the fungal infections, the locations' geographic coordinates were noted. Seven diseases were identified, including foliar anthracnose, gummosis, bud blight, powdery mildew, pestalotiosis, leaf yellowing and red rust. The different symptoms were isolated on Potato-Dextrose-Agar (PDA) medium in order to obtain fungal strains which were observed under the microscope. The associated pathogens were Colletotrichum gloeosporioides, Cochliobolus lunatus, Lasiodiplodia theobromae, Pestalotia heterocornus, Oidium anacardia and Cephaleuros virescens. Anthracnose, gummosis, and pestalotiosis were the most common diseases at the locations. Depending on the location, the disease incidence ranged from 4.44% in Kénieba to 51.66% in Dialakoroba. As function of severity index, it ranged from 1.97% for red rust to 22% for bud blight. To increase production and optimize cashew trees' economic potential in Mali, appropriate control measures must be deployed.