Nancy Njeru was a PhD Crop Protection student at the University of Nairobi (2017-2020). She is currently a Research Scientist at the Regional Laboratory for Mycotoxin Research and Capacity Building located at Kenya Agricultural and Livestock Research Organization (KALRO), Katumani, Machakos County, Kenya, where she leads daily activities in the Lab, oversees technical aspects of Aflasafe manufacture, in the Aflasafe factory, coordinate activities with other departments and supervisors, observe work and ensure employees are working according to standards, create schedule and assignments, and ensure safety and maintenance of staff. Her research and professional interests include microbiology, mycology, food safety and crop protection. Nancy received her BSc in Microbiology and Biotechnology and MSc in Microbiology from the University of Nairobi. Her MSc research was on: Influence of cropping systems and crop residues on the occurrence of Fusarium Head Blight of wheat (Triticum Aestivum L.) and associated mycotoxins in Narok County, Kenya. She has published in peer reviewed journals and presented in international conferences.
Abstract
Push-pull is a cereal cropping system that has recently been reported to reduce incidences of ear rots and mycotoxins in maize. However, the effectiveness and mechanism involved is not yet understood. This study determined, the (i) socio-economic and agronomic factors associated with the occurrence of ear rots and contamination of maize with mycotoxins in different cropping systems in western Kenya, (ii) impact of insect management under push-pull cropping system in managing aflatoxin and fumonisins, (iii) role of soil health improvement under push-pull on the population of mycotoxin-producing fungi and (iv) effect of desmodium roots exudates on mycotoxin producing fungi of maize.
Knowledge on aflatoxin was higher among elderly aged 45 to 60 years while knowledge of ear rots increased with level of education and non-push-pull respondents were more knowledgeable. Aflatoxin levels significantly increased with stemborer infestation of maize. Stemborer and fall armyworm damage, Fusarium ear rot infection, A. flavus and F. verticillioides populations were significantly (P < 0.05) reduced under push-pull cropping system. Aflatoxin levels were not significantly different between cropping systems, but fumonisin were significantly lower under push-pull cropping system. There was positive and significant correlation among insect damage, ear rot, ear rot fungi and mycotoxin levels in maize. Populations of fungi and nutrients in soils were not significantly different between the cropping systems. Desmodium extracts roots significantly reduced radial growth of toxigenic A. flavus and F. verticillioides through reduced spore germination and germ tube elongation. In conclusion, planting maize under push-pull cropping system indirectly reduced mycotoxin contamination.
Research Supervisors
Prof James W Muthomi _ University of Nairobi
Dr John M Wagacha _ University of Nairobi
Prof Zeyaur R Khan _ Internation Center of Insect Physiology and Ecology (icipe)
Dr Charles AO Midega _ icipe
