I shall consider emerging pathogens from an epidemiological perspective designed to advise government and other agencies on risk assessment and effective deployment of control measures. Drawing on examples of emerging pathogens of wheat, cassava, citrus, maize and sugar-beet that threaten crop production in Africa, India, US and UK, I shall discuss approaches to assess the risk of pathogens arriving, what the impacts are likely to be, where to survey, when, where and how to deploy control. Particular challenges arise in estimating dispersal parameters, allowing for uncertainty including cryptic infection and in coupling epidemiological with economic models. I propose to consider control at the regional and country-wide scales and to show that success involves matching the scale of control with the intrinsic spatial and temporal scales of epidemic spread. Grower behaviour is also important and we show how a small change in compliance can undermine the effectiveness of control strategies such as the introduction of clean seed schemes. The intention is to show that instead of starting afresh each time, there is an emerging epidemiological framework and a set of epidemiological tools that can adapted for each new pathogen.