Seed infection to pod and stem blight (Diaporthe phaseolorum) is severe at summer type soybeans maturing at hot and humid conditions. In order to increase germination and plant stand, this experiments were evaluated the effects of fungicide Benoram(Benomyl 20% ${pm}$ Thiram 20%) seed treatments with different seed sizes on emergence yield at field conditions, and with different infection degrees to pod and stem blight on germination in laboratory. Benoram treatment on seed was improved emergence rate and elongated hypocotyl not increased growth and yield. It was clearly improved length but germinations and germination speed by Benoram fungicide treatment on severely infected seed however was not improved germination rate at good quality of seeds and the effect was higher at large seed cultivar than small ones.