Field assessment of plant derivative compounds for managing fungal soybeandiseases

Natural plant-derived compounds are currently being explored as alternative s for pest control in sustainable agriculture. This study explored the use of two compounds, sesamol and carbenoxolone, in the management of the funga l soybean disease charcoal rot (Macrophomina phaseolina). Previous studies have determined that sesamol and carbenoxolone compounds significantly inhi bited fungal pathogen growth and plant disease in vitro. In order to assess the field efficacy of these compounds for fungal disease control, 2 years of field testing of these compounds have been conducted in southeast Kansas . Field treatments of the compounds sesamol and carbenoxolone at three conc entrations, 0, 500 and 1000 mug/ml, were applied foliarly at four distinct plant developmental stages. Treatments were applied to plots in random trip licate array and the experiment was repeated during the 1998 and 1999 growi ng seasons. Disease assessments were based on visual disease ratings, plant mortality and soybean yield analysis. Data were recorded weekly for each t reatment plot and statistically analysed using analysis of variance. Result s indicate that sesamol and carbenoxolone treatments significantly decrease d disease symptoms (11-12%) and plant mortality (24-28%) while significantl y increasing soybean yields (18-38%). These results support that plant-deri ved compounds can have a significant impact on soybean disease management a nd yield under field conditions.