It is worth mentioning that zoospores are highly sensitive to the chemical environment. For example, a high concentration of salts would trigger encystment of zoospores, which means zoospores shed the flagellum and fuse the membrane to form a walled cyst. This can be recognised as a self-protective strategy. But interestingly, even a high concentration of attractants would trigger the encystment of zoospores, which is believed to be the path towards zoospore settlement and parasitism. Hence control of the zoospore environment within the channels would seem to be important and could easily be obtained in the design presented in Figure , by adjustment of the attractant solution.