In high wine-producing regions, Grape Powdery Mildew (GPM) accounts for 75% of total pesticide use applications. If the grapevines are not properly treated until harvest, the presence of GPM in harvest grape clusters substantially depreciates the value of the entire crop. This project aims to develop a methodology to turn off specific grapevine genes (susceptibility genes [MLO]) and Powdery Mildew-related genes essential for the pathogen’s life cycle.

The primary objective was to examine the systemic movement of the dsRNA molecules within a plant. The validation of both dsRNA species related to VitviMLO6 and 17 acting in roots and leaves suggested the likely systemic move, via the vascular bundles, toward the upper part of the leaves once absorbed from the roots. Additional work to encourage the germination of Powdery Mildew spores to better prove the movement to the upper plant parts as well as find ways to produce higher-quality monodisperse nanoparticles instead of clumps of particles will lead to ease in future field delivery methods.