Grape sour rot is one of the major constraints to grape production in warm and wet growing regions. Sour rot is caused by the interaction of yeasts, acetic acid bacteria and vinegar flies. Berry injury is considered an important factor determining the severity of sour rot. Injuries in berries can be caused by feeding of yellowjackets, larval tunneling of grape berry moth (GBM), physiological factors and bird pecks during the sour rot susceptible part of the season in vineyards, especially for thin skinned and tight clustered grape cultivars. Although injuries may open entry holes for microbes and expose substrate for egg laying by vinegar flies such as Drosophila melanogaster, no studies have been conducted to experimentally test the hypothesis that these types of injuries enhance sour rot incidence and severity under field conditions. Our study aimed to a) understand the role of injuries caused by several common agents in vineyards on sour rot severity in the presence and absence of D. melanogaster, b) assess how these injuries impact the reproductive output of D. melanogaster, and c) survey the most prevalent wasp species, especially those belonging to Vespula genus (yellowjackets), in vineyards in 2021 and 2022. Our results show that sour rot severity (% infected berries in a cluster) of mechanically injured clusters was greater in both years than other treatments, especially in the presence of D. melanogaster. We observed a similar pattern with feeding damage from yellowjackets, though the enhanced effect of D. melanogaster was only significant in 2022. Feeding injury by grape berry moth larvae had minimal impact on sour rot severity, except in the presence of D. melanogaster in 2022. Vespula maculifrons and Vespula germanica were the most dominant yellowjacket species observed in vineyards along with a few other Vespula species, Polistes species and Dolichovespula species. Yellowjackets were found to equally explore healthy and sour rotted clusters. The understanding of the role of injuries in grape berries on sour rot severity and the knowledge of the dominant species of yellowjackets capable of directly injuring grape berries may help in developing sustainable management tactics against the grape sour rot complex.