Impact of silver nanoparticles and two biological treatments to control soft rot disease in sugar beet ( Beta vulgaris L)

Background Soft rot disease caused by Pectobacterium carotovorum was observed in various crops which lead to yield shortages and economic losses. Main body Therefore, both in vitro and in vivo experiments, aim to assess the effect of nanoparticles and biological treatments to control soft rot disease in sugar beet plant. The treatments comprised three silver nanoparticles (Ag NPs) concentrations (50, 75, and 100 ppm), three Spirulina platensis extract concentrations (50, 75, and 100%), and Bacillus subtilis (1 × 10 9 CFU ml) 100%. Under in vitro condation, results of the antibacterial activity showed that the zones of inhibition recorded 4.33 cm for 100 ppm Ag NPs, 0.43 cm for 100% algal extract, and 0.2 cm for bacterial treatments. Also, disease incidence % of bacterial soft rot was significantly decreased in all treatments in pot and field experiments. For resistant enzymes activity, B. subtilis 100% showed the most effect (84 mg min −1 ), followed by S. platensis extract 75%, (57 mg min −1 ), and Ag NPs 75 ppm (44 mg min −1 ), for poly phenol oxidase (PPO) at 81 days after sowing (DAS), but at 102 DAS revealed opposite results. On the contrary, peroxidase (PO) at 81 DAS showed different effects where treatment with S. platensis extract 100% increased it significantly (0.546 mg min −1 ) compared to control (0.535 mg min −1 ). The same trend was observed at 102 DAS. These results were reflected on sugar quality where Ag NPs 100 ppm treatment recorded the highest significant value (20.5%) followed by S. platensis 75% (19 %); however, the differences among them were not statistically significant. Conclusion This study indicated that the potential benefits of using silver nanoparticles and two biological treatments to control soft rot disease in sugar beet ( Beta vulgaris L).