According to this review article, titled "Short History of Malaria and Its Eradication in Italy With Short Notes on the Fight Against the Infection in the Mediterranean Basin",

In Italy at the end of 19th Century, malaria cases amounted to 2 million with 15,000–20,000 deaths per year.

They tried free distribution of quinine, and, as you have mentioned, vector control, which involved draining marshes and spraying DDT and other insecticides:

The campaign for the eradication of malaria from the whole national territory began in 1947 and ended virtually in 1948, with the total interruption of transmission of falciparum malaria. Indoor treatment with DDT (2 g of active ingredient per m2) of houses, stables, shelters, and all other rural structures continued into the mid-1950s and even later in some hyperendemic areas. (Figure 8). The results of the first two years of the year of DDT campaign were communicated by Missiroli in the IV Congress of Tropical Medicine and Malaria in Washington in 1948 under his vice-presidency.32 On that occasion Missiroli received unconditional awards. The continuation of the vector control campaign led to a further lowering of anopheline density and kept the interruption of the transmission of malaria.33 The last endemic focus of P. vivax was reported in the province of Palermo, Sicily, in 1956, followed by sporadic cases in the same province in 1962. The World Health Organization declared Italy free from malaria on November 17, 1970. Since then, almost all reported cases have been imported.

It is curious to note a parallel with a current involvement of philantropists in fight against malaria - back in 1920s and 1930s it was Rockefeller Foundation that funded the creation of Malaria Experimental Station and Institute of Public Health in Italy.