text: The term droplet is a diminutive form of drop – and as a guide is typically used for liquid particles of less than 500 μm diameter. In spray application, droplets are usually described by their perceived size (i.e., diameter) whereas the dose (or number of infective particles in the case of biopesticides) is a function of their volume. This increases by a cubic function relative to diameter/6000 to convert µm into picolitres)-->; thus, a 50 μm droplet represents a dose in 65 pl and a 500 μm drop represents a dose in 65 nanometers.