A precise and accurate method for delivering conidia of powdery mildew (Blumeria graminis f. sp. hordei) onto artificial and natural substrates was developed for use in studies to optimise the bioefficacy of crop protection agents. This included a modification of a Potter laboratory spray tower by the incorporation of a nylon mesh membrane capable of vibration in a variable and controlled manner by an audio signal generator, amplifier and low power speaker. The method allowed the even delivery of varying density distributions of conidia onto experimental surfaces such as glass, agar and leaves. This paper describes the design and construction of the apparatus and its efficacy in delivering conidia onto target surfaces in a quantitative and reproducible manner.