Escalating disagreements between mother and wife

My wife and mother are having tense disagreements. In the past, they've had minor differences. For example, my wife would complain to me my mother is too overbearing; my mother would complain my wife is lazy. However, it's intensified lately. I think the cause is my wife talked back to her once. Now, any little disagreement is magnified, leading to major disagreements. What can I do?