
rotten / bad apple spoil the (whole) barrel / bushel / bunch
/ɹˈɑːʔn̩ bˈæd ˈæpəl spˈɔɪl ðə hˈoʊl bˈæɹəl bˈʊʃəl bˈʌntʃ/
sentenceused to imply that a single bad or negative element within a group can have a harmful or corrupting influence on the entire group, leading to a decline in overall quality or integrity
