Effet de différentes conditions agro-écologiques sur le développement de l'anthracnose des baies du caféier Arabica dans l'ouest du Cameroun : incidence sur le mode de conduite des plantations et l'application des traitements phytosanitaires

The Arabica coffee production zone is located in western Cameroon and extends over a region approximately 150 km in diameter, at an altitude of between 900 and 1,800 m above sea level. The climate is characterized by unimodal rainfall distribution from March to November and a dry season from December to February. Most of the plantings cover 2 to 3 ha or less and are planted with a local variety susceptible to coffee berry disease, under plantain banana or fruit tree shade. A precise analysis of berries fall in technically limited smallholdings representative of the farming methods in this production region made it possible to distinguish between losses actually attributable to the disease and those due to other phenomena. The disease mostly occurs at medium to high altitude, where around 40% of plantings are located. By monitoring berry fall on a weekly basis, it was determined that losses due to "physiological fall" could be substantial, reaching up to half of total losses. The infection process appeared to occur earlier and induce greater losses on trees in full sunlight than on shaded trees. Knowledge of agroecological conditions propitious to disease development is essential for establishing a plantation management strategy and providing information as to the best time to trigger the phytosanitary treatments to be applied depending on the trees' environment. (Résumé d'auteur