Effect of Different Leaf Blotch Disease Management Treatments on Curcumin Content and Rhizome Quality of Turmeric (Curcuma longa L.)

Abstract

Turmeric (Curcuma longa L.) is an economically important spice crop valued for its principal bioactive compound, curcumin, which possesses significant medicinal and industrial importance. However, leaf blotch disease caused by Taphrina maculans adversely affects plant health, leading to reduced rhizome yield and quality. The present study was undertaken to evaluate the effect of leaf blotch disease management on curcumin content in turmeric rhizomes. A field experiment comprising seven treatments arranged in a completely randomised design (CRD) with three replications was conducted during the kharif season of 2023–24 at the AICRP on Spices, Asond Block, Coastal Experiment Station (CES), Wakawali, Maharashtra. Rhizome samples collected from each treatment at harvest were analysed for curcumin content in the Department of Soil Science using the modified spectrophotometric method of Sadasivam and Manickam (1992). The treatments differed significantly in curcumin content. Among the treatments evaluated, foliar application of Hexaconazole 5% EC and Tebuconazole 25.9% EC recorded the highest curcumin content (3.96% and 3.82%, respectively), indicating their superior efficacy in maintaining rhizome quality under leaf blotch disease conditions. Trichoderma spp. treatments also maintained higher curcumin content than the untreated control, although their effectiveness was comparatively lower than that of the fungicidal treatments. The findings indicate that effective management of leaf blotch disease not only suppresses disease severity but also maintains curcumin accumulation in turmeric rhizomes, thereby improving rhizome quality and market value.