Effect of vermicompost and vermicompost tea on white rot disease (sclerotinia sclerotiorum) of common beans and plant development

The aim of this thesis was to investigate the effects of vermicompost (VC) and vermicompost tea (VCT) on Sclerotinia sclerotiorum (Lib.) de Bary, the causative agent of white rot in common bean (Phaseolus vulgaris L.), and their contribution to plant growth. The research was conducted in two stages including in vitro and pot experiments in a climate chamber. In the first stage of the in vitro tests, VCT prepared by filtering with cold sterilization method was added to the medium at different concentrations (0.25%, 0.5%, 1.0%, 1.5%, 2.0%). In the second stage, the direct effects of VCT on mycelial development of S. sclerotiorum were determined. It was determined that cold-sterilized VCT significantly reduced mycelial development of S. sclerotiorum in a dose-dependent manner. A 2% concentration of VCT suppressed mycelial development of the pathogen by 79.2%. In the case of dual culturing of VCT and S. sclerotiorum, bacteria in tea suppressed mycelial growth of the pathogen by 47.4%. In pot trials, VC and VCT were applied at various concentrations (VC, 1%, 2%, 3%; VCT, 0.5%, 1%, 1.5%), both alone and in combination with the pathogen. The pathogen was inoculated directly into the root zone. The findings showed that VC and VCT applications reduced disease severity with increasing doses. VC added to the growing medium at 1-3% reduced disease severity by 44.9-73.5%. Similarly, VCT at 0.5-1.5% doses reduced disease severity by 51.1-65.3%. The most pronounced positive effect on plant growth was achieved with 1.5% VCT, which resulted in the highest values for biomass accumulation as well as plant and root lengths. Overall, the findings demonstrate that the use of VC and VCT can reduce disease severity and promoting plant development. In conclusion, the use of VC and VCT at appropriate doses can be considered as environmentally friendly and effective alternatives in terms of biological control and sustainable agricultural practices.