Historical data on fungal contamination of maize (Zea mays L.) from different agroecological zones in Nigeria: a review

Fungi attack maize in the field, and if warm and humid conditions that are suitable for fungal growth and mycotoxin production prevail, they can grow rapidly during storage, causing loss of quantity and quality, a reduction in nutrient content, and mycotoxin production in the crop. Most of the world's maize is lost to disease during storage, especially in developing countries. The three main genera that flourish in warm regions such as Nigeria and produce mycotoxins are Fusarium, Penicillium and Aspergillus. In this review, only 34 publications on the fungal contamination of maize from five agroecological zones of Nigeria where maize is grown were found and used for the study. The results of these works revealed that 39 different fungal genera comprising 36 and 3 genera of moulds and yeasts, respectively, are the major mycological contaminants of maize in Nigeria. The most common types of mould were Aspergillus spp. with an occurrence frequency of 37.31%, Fusarium spp. (23.13%), Penicillium spp. (13.76%), Rhizopus spp. (5.43%), Mucor spp. (4.71%), Botryodiplodia spp. (1.44%), Cladosporium spp. (1.44%), and Curvularia spp. (1.08%). Mould contamination was more prevalent in farm samples (39.49%) than in market (33.12%) and storage (27.49%) samples. This review revealed that there has been an upsurge of new fungal species that contaminate the maize consumed in Nigeria during the last decade. The reported presence of many harmful toxigenic fungi in this work, which presents the maize fungal pathogens from different agroecological zones of Nigeria since 1960, raises serious concerns with respect to postharvest losses, food insecurity, and public health.