2025/11/02 by Orisajo, S. B., Ogundeji, B. A., Daramola, F. Y. +2
#Microbial diversity #Physico-chemical #cacao #dieback disease #fungi #soil-borne microbes
paper · doi:10.82552/njhs.v29i4.49-59
Rhizosphere microorganisms play important roles in a cocoa ecological system. This study evaluated the microbial diversity of rhizosphere microflora in dieback-infested cocoa fields in Bende, Ikwuano, and Umuahia North Local Government Areas (LGAs) of Abia State, Nigeria. Subterranean rhizosphere microbes were obtained randomly from selected cocoa farms in the three LGAs. Associated bacteria and fungi species were assayed on Nutrient Agar (NA) and Potato Dextrose Agar (PDA) using the culture technique. The soil samples were analysed for physical and chemical properties using standard procedures. Eight bacteria species were isolated from the samples, out of which Bacillus subtilis, Pseudomonas putida, and Micrococcus spp., occurred in rhizospheric soils collected from the three LGAs. Eleven fungal isolates were obtained, with Penicillium notatum and Fusarium sp. occurring in all the samples. Total colony counts for bacteria and fungi ranged between 2.60 x 105 - 1.65 x 106 cfu/g and 2.0 x 106 – 3.5x106 cfu/g, indicating a higher fungal population across sample sites. A negative correlation existed between microbial populations, physical and chemical parameters except for the sand content and base saturation values. This study provides insights into the diversity and distribution of rhizosphere microflora of dieback-infested cocoa fields in South-East Nigeria. It further narrows the knowledge gap on potential biological indicators of early disease detection and monitoring, which are key to deciding suitable control methods.