The Great Depression affected Argentina and Brazil similarly in many ways.
Brazil's most valuable export at the time was coffee, a commodity who's value hit an all time low during the late 1920's. Some economists beleive that the Great Depression had a greater impract on Brazil than on the U.S. In a somewhat ironic twist, the depression actually let to Brazil's modernity. As the government of Washington Luis fell under more and more pressure, a political alliance under populist Geutilo Vargas rose to power and began to aggressivly pursue industrialization. Vargas also turned Brazil into a police state in the process, so the Great Depression's legacy in Brazil is one of modernity and totalitarianism. Vargas would remain in power until he was deposed in a 1945 military coup.
Argentina followed a similar patter. The crash of 1929 brought Argentina down from having the 4th largest per capita GDP to below poverty levels. A resulting military coup placed Jose Uriburu in a position of power, and soon he was cracking down on left-wing radicals. He was soon replaced by another General, Agustin Justo, who tried to help the sagging economy by making beef deals with the United Kingdom. When international trade collapsed, Argentina also pursued industrialization and soon they were on a similar path to that of Brazil.