Correlation between Maize Lethal Necrosis Disease and Mycotoxin in Maize in Bomet, Narok and Nakuru Counties, Kenya.

Abstract

Maize Lethal Necrosis Disease (MLND) is believed to increase concomitant toxic fungal infections in maize. The goal of this study was to discover a link between MLND and fungal infections. During the 2018/2019 maize growing seasons, a Randomized Complete Block Design experiment with three replicates was set up in farmer's fields in three experimental sites in Bomet, Narok, and Nakuru Counties. Six hybrid maize varieties classified as resistant (KATEH16-02 and DK777), tolerant (WE5135 and WE5140), and susceptible (DUMA 43 and PH30G-20) to MLND were used. A total of 54 maize grain samples were collected. Fungal colonies were isolated on Potato Dextrose Agar medium and identified using morphological and microscopic techniques. ELISA test was used to quantify aflatoxins. The samples yielded 4561 fungal isolates, with Fusarium being the most predominant genus (79.75%), followed by Penicillium (16.03%) and Aspergillus (1.933%). A positive significant correlation between the MLND bioassay score, Penicilium and Aspergillus infection was achieved, (r = 0.429, p =0.001) and (r = 0.275, P =0.5) respectively. Aflatoxin concentration levels of between 0.3 and 2.8 μg/kg were detected in 38.89 % of the samples. Aflatoxin and MLND were significantly correlated (p =0.001, r2=0.547). Although this study was only able to show Aflatoxins, there is a strong likelihood of other mycotoxins occurring in maize grains in higher proportions. Therefore the public should be made aware of the mycotoxin risks associated with consumption of MLND infected maize.