Management of Charcoal Rot (Macrophomina phaseolina) of Fenugreek in Rajasthan

Abstract

Background: Charcoal rot of fenugreek caused by Macrophomina phaseolina is destructive disease of all fenugreek growing areas of Rajasthan, The disease is wide occurrence in sandy soil of Rajasthan, where the climatic conditions are dry and temperature remains high. Under severe infestation it cause 35.00-42.56% losses in yield. In the present investigation, our main emphasis was to find out some new fungicides alone and combination with bio-agent for management of charcoal rot of fenugreek. Methods: Eight fungicides viz., captan 70%+ hexaconazole 5% WP, azoxystrobin 18.2% + difenaconazole 1.4% SC, chlorothalonil 75% WP, carbendazim 12% + mancozeb 63% WP, tebuconazole 50% + trifloxystrobin 25% WG, carboxin 37.5% + thiram 37.5% WP, copper oxychloride 50% WP and captan 70% WP were tested at different concentration of 100, 200, 300, 400 and 500 ppm against M. phaseolina using Poisoned Food Technique in vitro. The in vivo study was taken to evaluate the effect of one fungal and one bacterial bio-agent viz., T. harzianum, P. fluorescens was applied as seed treatment, soil dressing and soil application @ 5+5g/kg and @ 10 kg/ha respectively and fungicides viz., tebuconazole 50%+ trifloxystrobin 25% @ 1.5 g/kg, carbendazim 12% + mancozeb 63% @ 2 g/kg and azoxystrobin 18.2% + difenaconazole 11.4% 2 ml/kg seed were used in different treatments. The experiment was conducted at Experimental farm COA, SKRAU, Bikaner during Rabi 2020-21 on most popular cv. Rmt-305 in RBD design with the application of seed treatment, soil dressing and foliar spray of different fungicides with bioagents at different concentrations against Charcoal Rot disease and compared with an untreated control. Result: Among all the tested fungicides used in the present investigation, tebuconazole 50% + trifloxystrobin 25% WG found most effective in controlling the mycelium growth of pathogen. In field condition, it gave maximum disease control (85.72%) with highest grain yield (19.83 q/ha) when applied as seed treatment with tebuconazole 50% + trifloxystrobin 25% WG @ 1.5 g/kg seed + soil application of T. harzianum @ 10 kg/ha + SD with tebuconazole 50% + trifloxystrobin 25% WG. These treatments can provide an effective management of charcoal rot disease for fenugreek cultivators.