Biological control of fusarium root rot of Indian mulberry (Morinda officinalis How.) with consortia of agriculturally important microorganisms in Viet Nam

Background Fusarium root rot disease in Indian mulberry (Morinda officinalis How.) (FRRBK), caused by Fusarium proliferatum (FP), is widespread and responsible for serious economic losses in Viet Nam. The efficacy of a new bio-product named MICROTECH-1(NL) is compared with other commercial products for suppression of FP under in vitro, pot, nursery as well as in the field conditions. Results In in vitro antagonistic assay, MICROTECH-1(NL) significantly inhibited the mycelial growth of FP (72.38%). Under pot conditions, the efficacy of all the bio-products was significantly higher when applied prior to pathogen inoculation. The disease severity of treatments with double application of MICROTECH-1(NL) (applied both in the nursery and in the pot soil) was only 15.56%, significantly lower than control (80%). Thus, the application of MICROTECH-1(NL) significantly reduced the incidence of FP and markedly increased the number of plant beneficial bacteria and actinobacteria in rhizoplane of M. officinalis compared to untreated control. In the field conditions, double application of MICROTECH-1(NL) (both in the nursery and in the field soils) significantly decreased disease severity in comparison to single application in nursery or field. Conclusion The most effective treatment was double application of MICROTECH-1(NL), which significantly reduced the disease severity and FP population in roots of M. officinalis and increased the population of plant beneficial microbes.