This study was examined the characteristics of the pollinating activities of Apis mellifera, Bombus ignitus and B. terrestris as pollinators on the watermelon flowers(Citrullus vulgaris Schrad), and the effects of the pollination by pollinators compared to the artificial pollination in the watermelon greenhouses in Nonsan City on summer season in 2005. As a result, B. ignitus and B. terrestris could not be used for the summer season, because the bumblebees were not pollinated effectively indeed even two days after hives were released at watermelon greenhouses during the summer cultivating period. It could not be controlled a poor watermelon house conditions; high temperature and low humidity in the summer season which were the bad environment for pollinating activities of bumblebees. But this study was showed that A. mellifera could be used comparatively good pollinator instead of artificial pollination in spite of the bad environment for bees within the watermelon greenhouses in the summer season.
