This is an article by Nicholas Pileggi, "Anatomy of the Drug War," from January 1973. He writes of a self-imposed 10-year ban on drug dealing by the mafia, which ran from 1962 until 1972. Pileggi makes a number of interesting remarks:

(1) "Gambino has been importing foreign-born mafiosi like Buscetta for several years, and police intelligence officers suspect that much of the pressure being applied to organized crime leaders to return to narcotics has been exerted by these old-world imports."

(2) "The Bonanno's have been well known as a drug family since the early 1930s, when Joseph Bonanno first put the Sicily-Marseilles-Montreal-New York route together. The Bonanno mafia family has always been divided evenly between Montreal and New York . . . . It is the remnants of the old Bonanno family who are most in need of the drug trade, and it will therefore fall to Rastelli in New Jersey to take on the well-organized and deeply entrenched Cuban gangs"

Full article here = https://books.google.com/books?id=noI5n-RRLi8C&pg=PA33&lpg=PA33&dq=