Fusarium poses food and feed safety problems because most species produce mycotoxins. To understand the epidemiology of the F usarium disease, efforts must focus more precisely on how environmental variables affect disease presence. The objectives of the present study were to monitor the occurrence of F usarium species in maize kernels in northwestern S pain to determine the risk of mycotoxin contamination and to identify environmental traits affecting the composition of the F usarium species identified. A combination of 24 environments was evaluated. The percentage of kernels infected by F . verticillioides ranged from 33 to 99%, supporting the idea that fumonisin contamination is the main maize‐based feed and food safety concern in this area. In this region, temperature and humidity primarily affected F usarium spp. occurrence. Warmer temperatures during the later stages of kernel development and during kernel drying increased the frequency of F . verticillioides in maize kernels, while the presence of F . subglutinans was increased by higher relative humidity during the silking stage and cooler temperatures during kernel drying.