26 June 1959
The potato boycott began in protest against slave-like labour conditions for Black workers on potato farms. In areas like Bethal in Eastern Transvaal  (now Mpumalanga), recruited workers were expected to work long hours on farms in extreme weather conditions, receiving subsistence rations and slave wages. In articles in New Age the brutality of this system was exposed in 1947, nationalising the issue. Drum magazine took up the story in 1952, after coming in possession of a dossier of trials of cases of beatings in the late 1940s, including one case in which a worker had been beaten to death in 1944. In support of these workers, the South African Congress of Trade Unions (SACTU) launched a country wide potato boycott. The boycott, one of the most successful undertaken by the African National Congress (ANC) to that date, was called off in September 1959. Its success gave confidence to engage in further boycotts.  
References

Nair Billy, (2001). "Through the eyes of the workers", in Reflections in prison, Cape Town, Zebra.