Flystrike in sheep, mostly caused by Lucilia sericata (Diptera: Calliphoridae) has been consistently identified as one of the most important sheep diseases, from both a financial and welfare perspective (Bennett and others, 1999; Bennett, 2003; Bennett and Ijpelaar, 2005; Boyne and others, 2006). Infestation levels vary greatly depending on a wide range of factors related to the composition of the parasite fauna, the host, animal husbandry and control practices, climate and geography. However, it has been predicted that the season for flystrike will change (Wall and others, 2011), which, anecdotally, appears to be the case (Anon., 2012). Variation in the occurrence of flystrike in sheep, from year to year and area to area (Bisdorff and others, 2006), means that traditional preventative programmes are often not as effective as they used to be. A report in 2013, commissioned by the pharmaceutical industry (Wall and others, 2013) identified three key issues experienced by farmers: unpredictable weather patterns that make the timing of blowfly treatment difficult; increased risk of treatment resistance and the problem of treating parasites too late in the season. Early use of appropriate compounds for the prevention of flystrike aids effective control (Walters and Wall, 2012). With the aim to help farmers tailor their flystrike control programmes a simple website was developed (http://www.flystrikealert.co.uk/). The objective was for British farmers to be able to anonymously report when they encountered cases of flystrike in their flock.