Degradation of oxalic acid (OA) producing <i>Sclerotium rolfsii</i> (Sacc.) by organic biocides

Abstract

The aim of the study for the importance of oxalic acid produced by Sclerotium rolfsii during the invasion of host tissue during pathogenesis acts synergistically with endopolygalacturonase, lowering the pH of the infected tissues to a level optimal for the activity of this enzyme. Oxalic acid was the principal toxic agent produced in the culture filtrates of S. rolfsii and it was responsible for the death of host cells. The calcium present in structural pectates can be strongly chelated by oxalic acid. As a consequence, plant tissues are rendered more susceptible to invasion by S. rolfsii. Oxalic acid produced by S. rolfsii was very much reduced by Trichoderma viride (TVB1) (0.79 mg/ml culture filtrate), Pseudomonas fluorescens (SBHRPF2) 0.93 mg, neem cake (10%) (0.87 mg/ml), Lippia nodiflora (10%) and Lantana camera (10%) which were recorded as 2.12 and 2.25 mg/ml. The organic biocides that interfered with S. rolfsii led to reduction of oxalic acid production, which specifically reduced the disease incidence, and the oxalic acid degradation was a useful approach as a disease control strategy.