Well, other western countries did use DDT heavily, e.g. Italy[0]. Besides, it's not like the means used in the 1930s didn't have a significant ecological effect...
I'll note that the modern suggestions to eradicate Malaria are more nuanced and at least try to only affect the parasite/host. e.g. releasing sterile males, immunizing the mosquitoes against the parasite[1], ATSBs, a GM fungus to poison mosquitoes, making human blood deadly to the parasite[2], etc.
IMHO (I'm far from an expert), the most promising seems to be releasing sterile males followed by some of the other approaches to deal the death blow to the parasite (though if the mosquito goes I won't be bothered).
