Regional and seasonal activity predictions for fall armyworm in Australia

•We develop a spatial model of population growth and dispersal for the fall armyworm.•The model accurately predicts the native and invasive ranges across the world.•Populations could permanently persist in north-eastern Australia where susceptible crops are grown.•Adults that disperse into cooler regions may be constrained by winter temperatures and aridity.•Model outputs can directly inform management strategies for the pest moving forward.