DDT was proven totally successful in eliminating mosquitoes from infested swamps during the construction of the Panama canal thus making that project possible. The Dept of Ag under LBJ banned the substance as a farm product in spite of significant and substantial findings in a court of law that there was no harm in the use of DDT and that, in fact, it had substantial benefits to the health and well being, especially of poor and rural people in the south.
DDT was banned to get the early environmentalists off LBJ’s back. These were the same people and organizations that sought the means through Planned Parenthood and the War on Poverty to destroy the black population in the US.
In spite of spurious, superficial claims DDT has never been scientifically demonstrated to be other than a boon to health and well being.
DDT as an insecticide wasn't discovered until 1939. And the question isn't whether DDT is effective. It's is it more effective than what they are using now?