Evaluation of bioagents and chemicals for the management of mulberry root rot incited by Lasiodiplodia theobromae and Macrophomina phaseolina

Abstract

An experiment was conducted to study the efficacy of new generation fungicides and potential biocontrol agents against mulberry root rot disease complex caused by Lasiodiplodia theobromae and Macrophomina phaseolina. Four fungal antagonists viz., Trichoderma asperellum, T. harzianum, T. virens and T. koningiopsis, three bacterial antagonists viz., Bacillus licheniformis, B. amyloliquefaciens and B. subtilis and five new fungicides viz., azoxystrobin, tebuconazole, kresoxim methyl, tebuconazole + trifloxystrobin along with carbendazim were tested. It was observed that T. asperellum TRI15 recorded the lowest fungal mycelial growth (2.9 cm and 2.4 cm) against L. theobromae and M. phaseolina under in vitro. The fungicides tebuconazole and tebuconazole+ trifloxystrobin at 500 ppm and 1000 ppm recorded 100 percent of mycelial inhibition against both pathogens. In pot experiment, the root rot incidence was not recorded upto 60 DAI in treatment vermicompost + T. asperellum (TRI 15) @ 100 g/plant followed by soil drenching with tebuconazole 500 ppm. Under in vivo, soil drenching with tebuconazole @ 500 ppm/plant at 15 days after pruning recorded minimum root rot incidence (2.08 percent). soil application of vermicompost + T. asperellum TRI15 @ 100 g/plant recorded more number of branches/ plant (24.91 Nos.) and increased leaf yield per plant (0.8 kg).