Vol. 12, Issue 3 (2023)

Author(s):
Kedarnath, KT Rangaswamy, NB Prakash, Raghavendra Achari and Sabyasachi Majumdar

Abstract:
Powdery mildew disease is a serious and debilitating disease of tomato worldwide. The main objective of the study was to find out the efficacy of different concentrations of silicic acid on severity and its disease progress apart from defence responses against powdery mildew disease of tomato cultivated under greenhouse. The application of silicic acid @ 4 mL L-1 (35.24 Per cent Diseases Incidence-PDI) and @ 2 mL L-1 (59.05 PDI) recorded lowest disease severity when compared to untreated control (80.00 PDI) at 49 days after inoculation. Similarly, the lowest disease progress (Area Under Disease Progress Curve-AUDPC values) was recorded with the application of silicic acid @ 4 mL L-1 (690.13) and 2 mL L-1 (1016.63), whereas untreated plants recorded highest AUDPC value of 1873.34. The higher dry weight (16.58g), silicon content (1.15%) and increased chlorophyll content recorded with silicic acid @ 4 mL L-1 when compared to untreated control plant. The reduced severity and progression of disease on tomato leaves has been attributed to significant increase in activities of defence enzymes viz., peroxidase, polyphenol oxidase, phenylalanine ammonia-lyase, β-1, 3 glucanase and chitinase upon foliar application of silicic acid @ 4 mL L-1 and 2 mL L-1. This clearly illustrate that, foliar application of silicic acid on tomato leaves conferred the resistance against powdery mildew pathogen.