“Rock powder” obtained from the mechanical milling of natural bentonite rich in montmorillonite. The product is micronised to a level of fineness that prevents any clogging, thus protecting pumps, filters and atomiser nozzles. Bentonite bianca acts as a coadjuvant/adhesive for spring foliar treatments, controls moisture, preventing the proliferation of yeasts, bacteria and fungi, and limits the production of flavonols (quercetin).