Efficacy Assessment of Inhibitory Fungal Concoctions Against Mycotoxin Fungi Affecting Maize Grain Quality in Western Kenya

Abstract

Limited biological control products exist for use against mycotoxins in maize fields of Kenya’s smallholders. In response, this study aimed to assess the capacity of four fungal isolates to suppress the proliferation of mycotoxin fungi and disruption of fungal diversity in field conditions. Field assessments were done in Kibos and Sega sites of Western Kenya during the long and short rain seasons of 2020 while post-harvest assessments were done at University of Eldoret Crop Protection Laboratory. The experiment was laid in a split-plot arrangement in RCBD with four replications. The subplots consisted two susceptible varieties to aflatoxins (Duma and Punda milia) while the sub plots consisted seven treatments including Trichoderma harzianum, Monascus species, fungal isolate MCMT3, fungal isolate MCBT4b, co-inoculation treatment (Monascus sp, MCMT3, and MCBT4B), Aflasafe KE01TM (positive check) and control (negative check). Inoculations of the isolates were done at 7days after silk emergence at 4ml per ear, while Aflasafe KE01TM was applied two weeks before flowering. At post-harvest 5 grains per subplot were cultured in PDA in triplicates and incubated at 25-27oC aseptically. Data on percentage incidences of AF, OTA, PAT and PCN fungi, and number of diverse fungi was collected and subjected to descriptive statistics using Microsoft Excel Spreadsheet Software of Microsoft 365 version. Monascus spp. and T. harzianum concoctions best suppressed mycotoxin fungal incidences but did not differ significantly with MCMT3, MCMT4b, and the co-inoculation of isolates MCMT3, MCMT4b, and Monascus spp. Co-inoculation of Monascusspp., MCMT3, and MCMT4b displayed no synergism in suppressing mycotoxin fungi. In conclusion, Monascus spp., T. harzianum, MCMT3 and MCMT4bhave an inhibitory capacity against A. flavus, A. parasiticus, A. nomius, A. niger P. corrylophilum, and P. auratiogriseum in field conditions. Isolates MCMT3, MCMT4b and Monascusspecies are recommended to control mycotoxins in maize and other crops susceptible to toxigenic fungal infections.