Relationships between in vivo and in vitro aflatoxin production: reliable prediction of fungal ability to contaminate maize with aflatoxins

► Aflatoxin production in synthetic media is not correlated with aflatoxin production on viable maize kernels (in vivo). ► Incidences of falsely atoxigenic isolates are high in synthetic media. ► Aflatoxin production on autoclaved maize grain is highly predictive of aflatoxin production during infection of viable grain. ► Aflatoxin screens on natural host material are highly reliable in identifying causal agents of disease.