Sustainable management of plant diseases is vital for maintaining food security, particularly due to the significant importance of monocots in global agriculture. The utilization of conventional pesticides, however efficacious, raises concerns regarding environmental contamination, hazards to human health, and the emergence of disease resistance. Herein we propose smart nanocomposites (SNPPECs) that integrate biomolecules to activate the plant immune system, encapsulated in nanoparticles within a polyelectrolyte complex. The polyelectrolyte complex, composed of oppositely charged polymers, augments biopesticide retention by mitigating the hydrophobicity of the leaf cuticle via electrostatic interactions and lowering the surface tension of the formulation. In comparison to the naked biomolecules, the nanocomposites showed improved deposition by reducing the contact angle on rice leaves by 31°. Moreover, the control efficacy of SNPPECs against Xanthomonas oryzae pv oryzae was 87%. Our research illustrates the efficacy of nanocarriers in enhancing plant protection, thus aiding in environmentally sustainable disease management approaches.