The tool consists of three disks made of plastic-coated cardboard. Each disk has a different background color and represents a host resistance class (red = susceptible, yellow= moderately resistant, green= resistant) based on the 0 to 9 susceptibility scale, in which increasing susceptibility is represented by ascending numbers, with 9 representing high susceptibility. To attract young farmers, CIP and the National Institute for Agricultural Research (INIAP) of Ecuador have created a couple of disc-tool-based mobile apps. The idea is that farmers can use an app on their cell phone, without accessing the Internet, to decide whether a particular potato crop needs an application of fungicide, in accordance with the specific variety as well as local environmental conditions.