Evaluation of micro-fungi associated with leaf spot of Allanblackia floribunda Oliv. in Southern Nigeria

Fruit of Allanblackia floribunda is an active ingredient in the pharmaceutical industry. Fruit production in the species is hindered by incidence of pathogenic fungi leading to economic loss. This study was conducted to investigate micro-fungi species associated with leaf spot of A. floribunda. Field surveys were carried out in natural stands containing matured A. floribunda trees located at Owu Ikija, Ogun State (6.80°N, 4.03°E) and Benin, Edo State (6.29°N and 5.58°E) in Southern Nigeria. Diseased leaf samples were collected during wet and dry seasons. Pure cultures of fungal isolates obtained from the leaf samples were examined to determine their cultural and morphological characteristics. Percentage incidence of micro-fungi in each location was estimated. Leaves of healthy seedlings were sprayed with 104 conidial/ml spore concentration of fungal isolates to determine their pathogenicity. Fourteen fungal species were isolated from leaves of A. floribunda across the two sites. Aspergillus spp., Macrophomina phaseolina, Penicillium species, Pestalotia palmarum, Rhizopus nigricans and Trichoderma pseudokoningii were isolated from both sites during both seasons. Fusarium oxysporum, Lasiodiplodia theobromae, Penicillium javanicum and Pythium aphanidermatum were present at Owu Ikija while Colletotrichum capsici, C. coccodes and Curvularia lunata were present at Benin with fungal incidence of 12.5, 12.5 and 4.17%, respectively. P. palmarum had modal fungal incidence (35.29%) at Benin followed by T. pseudokoningii at Owu-Ikija with frequency value of 18.75 and 17.54%, respectively. P. palmarum was the most prevalent out of all micro-fungi species associated with A. floribunda in all locations. Pathogenicity test was negative for all tested isolates, variety of micro-fungi are associated with A. floribunda. Key words: Allanblackia floribunda, fruit, fungal isolates, leaf samples, pathogenicity.