Potencial fisiológico e sanitário de sementes de soja tratadas com Trichoderma spp. no controle de Sclerotinia sclerotiorum

Abstract

The sanitary and physiological quality of soybean seeds is compromised by their association with Sclerotinia sclerotiorum, affecting the initial establishment of the crop and contributing to disease dissemination in the field. The objective of this study was to evaluate the effect of different inoculum potentials of S. sclerotiorum on seed quality, as well as the efficiency of biological control using Trichoderma. The experiment was conducted in a completely randomized design, arranged in a 5×5 factorial scheme, consisting of five inoculum potentials (0, 6, 12, 24, and 48 hours) and five control methods (three Trichoderma isolates, a chemical fungicide, and water).Sanitary quality was assessed by fungal incidence, and physiological quality was determined through germination, radicle protrusion, emergence, and seedling length tests, complemented by analyses of speed, uniformity, growth, and vigor indices. It was observed that increasing inoculum potential resulted in higher pathogen incidence and a progressive reduction in seed quality. Under higher inoculum pressure, the chemical fungicide was more efficient in maintaining physiological performance. The biological control agents showed variable effects depending on the isolate; however, overall, they were able to mitigate the effects of the pathogen at intermediate inoculum potential. It is concluded that increasing the inoculum potential of S. sclerotiorum increases pathogen colonization and incidence in seeds. The physiological quality of seeds is progressively reduced as inoculum potential increases, affecting germination, emergence, and vigor. The fungicide showed greater efficiency in control, whereas biological control with Trichoderma spp. is influenced by inoculum pressure.