My understanding was that those horrible insecticides were the primary thing that worked. The link you posted mentions about draining breeding sites, but seems

My understanding was that those horrible insecticides were the primary thing that worked. The link you posted mentions about draining breeding sites, but seems to be saying that DDT application was the biggest component: "It consisted primarily of DDT application to the interior surfaces of rural homes or entire premises in counties where malaria was reported to have been prevalent in recent years."