Combination of irradiated chitosan and microbial agent to reduce downy mildew on grapevine cv. Thompson seedless

Abstract Globally sustainable disease management ensuring high quality in grapes is in demand as it holds significant importance as a versatile fruit for consumption, winemaking, and production of various products such as grape juice, raisin, and grape‐seed oil. The present paper reports a combination of nano‐biotechnology as a promising strategy for enhancing plant health and fruit productivity in grapes combining Irradiated chitosan nanoparticles and bio‐control agents. The Irradiated Chitosan with Bacillus subtilis and Trichoderma viridae and pesticides were evaluated for disease management. Percent disease index, percent disease control, and percent yield enhancement in Cymoxanil 8% + Mamcozeb 64% WP @ 0.2% treatment were as 17. 24%, 67.97% and 33.91% in 150 ppm Irradiated chitosan+ B. subtilis were 19.83, 63.16, 30.41 and in Trichoderma 150 ppm Irradiated chitosan were 24.58, 54.33, and 27.40, respectively as compared to untreated crop with disease severity 53.84% PDI. Thus, irradiated chitosan and Bacillus subtilis elucidated a synergistic combination for residue‐free efficient phytosanitary measures, which harnessed the strength of chitosan and bio‐control agents for sustainable grape productivity. These findings will also pave the way for a deeper understanding of the synergistic interaction between Irradiated nanochitosan and bio‐control agents for an eco‐friendly and economically viable disease management strategy. The minimum temperature and morning relative humidity (RH I) had positive significance, with correlation coefficients of 0.484 and 0.485, respectively. The evening relative humidity (RH II) had a positive highly significant positive correlation coefficient of 0.664. Chitosan merits as a multiple stress tolerance enhancing agent that will further help in mitigating climate change adaptations in grapevines reducing reliance on chemical agro‐inputs.