M. B. PATILSANGEETHA, B. M.2023-12-292023-12-292023-12-29https://krishikosh.egranth.ac.in/handle/1/5810204989Chilli is an important commercial vegetable cum spice crop. It suffers from various biotic stresses, among them chilli powdery mildew incited by Leveillula taurica (Lev.) Arn. is a major constraint which results in yield loss up to 42-50 per cent. Powdery mildew can be successfully controlled by chemical fungicides, but chemical residue in the harvested fruit is the main limiting factor for export. Hence, the present study was conducted in order to find out the better alternative for chemical fungicides for the management of chilli powdery mildew. Weather parameters like maximum temperature, minimum temperature, rainfall, rainy day, evaporation and sunshine hours were negatively correlated and morning as well as evening relative humidity were positively correlated with the disease severity. The optimal temperature and relative humidity for conidial germination was found to be 25 ± 1 °C and 85 per cent, respectively. Elevated CO2 at 550 ± 25 ppm with 2 °C rise in temperature supported maximum conidial germination (45.37 %). Application of bioagents and organic products were significantly induced the accumulation of defense enzymes viz., peroxidase (PO), polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL), catalase and total phenolics in the challenge inoculated chilli plants compared to control. Higher activity was noticed in resistant hybrid than susceptible one. Among the bioagents and organic products evaluated under in vitro against L. taurica, T. asperellum and NSKE showed highest spore germination inhibition (82.84 and 89.89 %, respectively) with less per cent germination of conidia (7.06 and 4.07, respectively). Under field condition A. quisqualis sprayed chilli plot showed least PDI (17.79) with maximum yield (24.44 q/ha) followed by T. asperellum (18.77 PDI and 24.29 q/ha) over control. Among the organic products NSKE at 5% showed least PDI (22.96) with yield of 23.48 q/ha.EnglishThesis