Currently, nanotechnologies are being actively introduced into agriculture, in particular in the field of creating new effective plant protection products. This is achieved through the development of nanosized controlled release systems, such as polymer nanoparticles, micelles, and so on using a wide variety of materials. In the present study, we applied original approach based on "green" mechanochemical technology to prepare new nanocomposites of pesticide Tebuconazole (TBC) for treating wheat seeds against pathogenic microflora (B. sorokiniana, Fusarium spp., Alternaria spp., Penicillum spp.). The size distribution of nanoparticles for three TBC formulations (microcapsules, microemulsionsб nanosuspensions) was measured using dynamic light scattering technique. All formulations contained nanoparticles (10-300 nm) and we aimed to find the most suitable size for effective penetration into cell membranes. The narrowest size distribution (225±40 nm) was observed for nanosuspension based on Licorice Extract (LE). The microcapsules based on Na-CMC also contained micro-sized particles (1,500 nm), which are apparently aggregates of nanoparticles. The laboratory and field biological tests revealed a high activity of the developed formulations against all pathogenic microflora under study, with a low retardant effect. Nanosuspension is considered as the most "environmentally friendly preparation", since it contains only natural LE as an adjunct. This formulation with a consumption rate of 0.25 Lt -1 suppressed 100% B. sorokiniana, Fusarium spp. and Penicillum spp. infections, possibly due to the presence of natural saponin glycyrrhizic acid, which interacts with plant membranes and promotes better penetration of TBC into the grain.