Harnessing Defence Inducers for the Management of Powdery Mildew in Linseed

Linseed experiences grain yield losses due to multiple abiotic and biotic stressors. Among these, powdery mildew, caused by Oidium lini Skoric, is a particularly significant biotic challenges. The diseases reduce grain yield and photosynthetic activity, leading to drooping, yellowing leaves, fewer capsules, and smaller seeds. To manage powdery mildew, defence inducers such as Salicylic acid (50 and 100 ppm), Monopotassium phosphate (1%), Sodium propionate (1%), and the fungicide Hexaconazole (0.1%) were evaluated from 2019–2020 to 2021–2022. Seed treatment and foliar application of salicylic acid at 50 ppm, administered at 30 and 45 DAS, resulted in the highest disease reduction (34.99%), seed yield (1219 kg/ha), and ICBR (6.71). The study highlights the potential use of SAR and ISR-based defence inducers as alternatives to conventional fungicides, particularly for managing powdery mildew in linseed.