Diversity and Environmental Specificity of Fungal Isolates from Soils and Cereal Grains in Western Kenya

Abstract

Background and Objective: Mycotoxin contamination in maize and groundnuts has undermined Kenya's health care system for decades. This study aimed to determine the diversity of mycotoxin fungi in maize, groundnut and soils of Western Kenya and farmers' awareness of on-field mycotoxin mitigation measures. Materials and Methods: Infected maize, groundnut and soil samples were collected from Homa Bay, Migori, Siaya and Busia Counties. Semi-structured questionnaires were used to collect socioeconomic data on mycotoxin awareness and mitigation measures used by farmers. Pure fungal isolates were obtained for diversity assessment on PDA and incubated at 25-27°C. A light microscope at ×400 magnification was used for the morphological identification of spores and mycelia, while species were identified using plant pathology reference books and journals. Results: Thirty-five diverse fungal isolates were obtained from all samples. The genus Aspergillus was the highest in terms of isolation frequency, with 14 diverse pathotypes, followed by Penicillium (8 isolates), Fusarium (4 isolates) and the rest (9 isolates). Busia County had the most diverse number of isolates, while Siaya had the least. Among sample categories, most fungi were obtained from soil samples (30 isolates) while maize and groundnuts recorded 19 and 9 isolates respectively. While 22 isolates were specific to counties, 13 were environmentally non-specific. Farmers in Western Kenya had partial knowledge of best pre- and postharvest mycotoxin mitigation practices. Conclusion: Mycotoxin-producing fungi were the most dominant fungi in maize, groundnut and soils of Busia, Siaya, Homa Bay and Migori counties of Western Kenya. These fungal species were highly specific to the environments.