Two field trials with 15 years old grapevines cv. Thompson Seedless (highly susceptible cultivar) were conducted at SadatCity, Menofyia governorate, Egypt. In these trials, treatments consisted of summer pruning, i.e. ( leaf removal , shoot removal , topping and the treatment with (leaf removal +shoot removal +  topping) in addition to the control vines (without summer pruning) . An additional trial , compared the cluster thinning treatment with the control ( without cluster thinning).All plots were established in a split –plot design with or without fungicides or gibberellin application  .The above mentioned treatments were applied during the growing season starting at full bloom till veraison stage ( the beginning of ripening ) in order to control grapevine bunch rot disease . The obtained results showed that the disease incidence and severity of bunch rot were best reduced by using any of the used gibberellin treatments compared to that of untreated vines . The greatest reduction in disease incidence and severity was occurred in the treatments with three sprays of gibberellin when the flower cluster was 10 cm³ long, Full Bloom and 6mm in berries diameter stage which summer pruning is done . In additional trial , cluster thinning also reduced disease incidence and severity in nonsprayed control compared to the nonsprayed control ( without cluster thinning). The greatest reduction in disease incidence and severity was recorded from the treatments with three sprays of  the fungicide (Euparen M) at bloom, pre-close and veraison. Also, the produced fruit yield from treated vines was significantly higher during the first and the second seasons in comparison with that of untreated vines.