Shelf life and efficacy of talc-based bio-formulations of Trichoderma harzianum isolates in management of Sclerotinia rot of Indian mustard (Brassica juncea)

Among the eight isolates of Trichoderma harzianum screened against Sclerotinia sclerotiorum, ecology of promising four was studied to prepare bio-formulations. T. harzianum isolates grew well at temperature 20°C, pH 5 and molasses agar medium. However, the highest number of colony forming units (c.f.u.) was observed for T. harzianum-P isolate while T. harzianum- GR isolates showed greater survival ability. Field trials were conducted to test the efficacy of these bioformulations against Sclerotinia rot disease caused by S. sclerotiorum in Indian mustard (Brassica juncea). The treatments were talc-based formulations of four T. harzianum isolates applied as seed treatment @ 5g/kg seed, soil application with farm yard manure @ 2g/kg and foliar spray @ 6g/l water. Seed treatment and foliar spray of garlic (Allium sativum) bulb aqueous extract @ 2% (w/v), recommended fungicide mancozeb @ 2.5g/l and carbendazim @ 1g/kg, respectively were applied. Highest reduction of Sclerotinia rot (69.0%) was achieved by T. harzianum isolate GR over control followed by soil application of T. harzianum isolate SI-02 with farm yard manure (60.8%) and foliar spray of garlic bulb aqueous extract (60.8%). Highest Trichoderma spp. population count was observed at 60 days after sowing (1880 cfu/g) in soil of T. harzianum-GR isolate applied in soil with farm yard manure. Plant stand was statistically higher in plots where T. harzianum was applied with farm yard manure in soil.