Surveillance of maize lethal necrosis disease in Nigeria

Abstract

Maize is a multipurpose crop and a staple food for millions of people in Nigeria but its potential yield is constrained by several viruses. Maize lethal necrosis disease (MLND) is a new virus disease ravaging maize farms in East Africa with attendant field abandonment and huge financial losses. Therefore, this study was conducted to determine the status of the disease in Nigeria. Maize farms in 25 Local Government Areas (LGAs) selected from Akwa Ibom, Cross River, Kano and Katsina were surveyed between May and August, 2017. A total of 108 symptomatic and asymptomatic leaf samples were collected and tested for Maize chlorotic mosaic virus (MCMV), Maize dwarf mosaic virus (MDMV) and Maize streak virus (MSV). None of the samples was positive for MCMV and MDMV but about 62 % of them reacted positively with MSV polyclonal antibody (PAb). The incidence of MSV was highest in Kano State (41.8 %), followed by Katsina State (23.9 %), whereas incidence of 20.9 and 14.9 % was found in Cross River and Akwa Ibom State, respectively. The negative reaction of all the samples to MCMV and MDMV polyclonal antibodies implied that the surveyed areas were free of MLND. The symptomatic samples that tested negative were probably infected by pathogens other than those investigated in the present study. Despite this positive result, there is need for continuous surveillance, information sharing and awareness campaign within Nigeria and with neighbouring countries. Plant breeders should also intensify research programme for the development of MLND resistant maize varieties.