Management of sorghum rust caused by Puccinia purpurea Cooke by employing an integrated approach
Sorghum (Sorghum bicolor L.) is an important cereal crop grown in semi-arid, subtropical, tropical and temperate regions and it ranks fifth in worldwide cereal crop production. Rust of sorghum (Puccinia purpurea Cooke) is an important emerging disease in most sorghum growing areas of the world, which can increase susceptibility to other pathogens. Thus, there is a need to focus more on managing the disease. An attempt was made to manage the disease by integrating effective fungicides, botanicals, indigenous technical knowledge (ITKs) and bioagents under in vitro and in vivo conditions. In vitro studies revealed that among the different fungicides, botanicals, ITKs and bioagents tested, tebuconazole 50 % + trifloxystrobin 25 % and hexaconazole 5 % EC recorded 100 % uredospore germination inhibition. Among the botanicals, turmeric extract at 25 %, neem extracts at 50 % (78.39 %) while panchagavya (52.07 %) and combination of Trichoderma harzianum (5 g/L) and Pseudomonas fluorescens (5 g/L) (82.91 %) which recorded highest mean per cent inhibition of uredospore germination irrespective of concentration tested. Among 11 integrated spray schedules evaluated in a field study at the Main Agricultural Research Station (MARS), Dharwad during rabi seasons of 2021 and 2022, tebuconazole 50 % + trifloxystrobin 25 % at 0.05 % was significantly superior spray schedule. It recorded the lowest per cent disease index (PDI) of about 16.01 with highest grain yield (16.25 q/ha) and cost-benefit ratio (B:C ratio) of 1.87 followed by hexaconazole 5 % EC at 0.1 % (18.84 PDI; 15.76 q/ha). However, the highest PDI (92.50), lowest grain yield (9.63 q/ha) and B:C ratio (1.17) was recorded in the unsprayed control. The findings of this study highlight the potential of integrated disease management approaches combining chemical, biological and botanical components to achieve sustainable and economically viable control of sorghum rust and enhance productivity under semi-arid agro-ecological conditions.