This study assessed the nature and effects of armyworm infestation in maize production in Nigeria. The objectives of the study were to explore the nature of the outbreak, farmers’ understanding and experiences about the effect of the pest invasion and the control measures adopted by the farmers. Data were collected using a structured questionnaire through a face-to-face interview. Descriptive statistics were used in the analysis of the data. Farmers were selected using purposive and multistage random sampling techniques. Results show that the armyworm outbreak has had very serious effects on maize production in the area, manifesting in the form of damage and unusual changes in the colour of the leaves, stems, and cobs. The majority of the respondents (98%) agreed that the outbreak started in 2016, and 85% agreed that the damage caused by the pest was to a great extent. About 53%, 14%, 12%, and 2% of the respondents used pesticides, regular weeding, local herbs and ashes, and removal of affected plants, respectively. Lack of awareness, inadequate pesticides, and low level of extension education were among the constraints identified in the control of the pest. Implementation of an integrated approach is therefore recommended for effective control of the pest.