Optimisation of Biological Control of Damping-Off of Sugar Beet (Beta vulgaris L. ssp. vulgaris var. altissima Doell) Caused by Pythium ultimum Trow by Using Pseudomonas fluorescens B5 (English shop)

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Suryo Wiyono’s dissertation investigates the optimization of biological control of sugar beet damping-off caused by Pythium ultimum using the bacterial antagonist Pseudomonas fluorescens B5. The research focuses on improving antagonistic efficacy and developing suitable formulation techniques for microbial plant disease control. Transposon mutagenesis is employed to generate bacterial mutants with increased production of antifungal metabolites, followed by laboratory and plant-based evaluations. Selected mutants demonstrate improved disease suppression compared with the wild-type strain. Particular attention is given to the role of indole-3-acetic acid (IAA) and hydrogen cyanide in inhibiting the pathogen. The study also examines how different sugar beet varieties influence biological control performance and bacterial colonization of root surfaces. Various carrier materials for seed pelleting are evaluated to improve bacterial survival and maintain antagonistic activity during storage. Additionally, nitrogen compounds and trace elements are investigated as formulation additives to enhance microbial growth and disease suppression. The findings highlight opportunities to improve biological control strategies through mutant selection, host variety compatibility, and optimized microbial formulations.