Scientific publications
Daniel Fotio
Julienne Nguefack
C. Zonkeng Guepi
O.A. David
Nounamo Laurent
Dominique Bordat
Appolinaire Tagne
P. H. Amvam Zollo
Agritrop (Cirad)
Bean is a high source of vegetal protein in Africa. However its culture suffers many constraints among which seed-borne diseases are of great importance. The purpose of this study was to collect common beans (Phaseolus vulgaris L.) and to survey the disease agents responsible for the low production of this crop in Cameroon, especially in the Centre Province of this country. Twenty five (25) varieties of common bean seeds were collected from different agroecological zones of Cameroon, and cultivated in a sole crop system at Minkoameyos (Yaounde, Cameroon) between the 07th of October 2003 and the 25th of January 2004. The experimental site was characterised by three soil indicators: low pH (5.53), low C/P ratio (81.95) and normal C/N ratio (22.40). The experimental unit consisted of area of 8 m2 (4 m x 2 m). The experimental design was a randomized complete block design with 3 replications. The record of disease symptoms started four weeks after planting using the Compendium of Bean Diseases. The Liquid Assay method allowed the identification of Xanthomonas axonopodis pv. phaseoli and its variant fuscans, Pseudomonas syringae pv. phaseolicola and Pseudomonas syringae pv. syringae as major agents responsible for the common and fuscous bacterial blights, halo blight and brown spot respectively, on infected leaves and seeds. In addition, symptoms of the following diseases were observed in the field: ascochyta blight (Phoma exigua var. diversispora), anthracnose (Colletotrichum lindemuthianum), angular leaf spot (Phaeoisariopsis griseola), floury leaf spot (Mycovellosiella phaseoli), bean common mosaic and black root (Bean common mosaic virus), and of insect pest "le cigare" (Apoderus humeralis). The yield average ranged from 0.046 t/ha to 0.821 t/ha. This low yield was correlated with disease damages observed in the field. (Texte intégral)
