I always get a little concerned when people start shouting bring back DDT. DDT lost its label due to overuse and misuse (bad science also played a part). The overuse and misuse causes resistance and outbreaks of secondary pests.
While I think DDT should get a new label, I would have it as a RUP pesticide only for use in structures for interior residual spraying.
Nearly all outbreaks of Euynomous Scale and Crepe Myrtle Aphid I have seen are due to spraying of synthetic pyrethroids to control mosquitoes.
When I lived in Africa, we had a lot of success by simply spraying palm oil on stagnant water. The oil forms a surface film, and this breaks the adhesion of the larva's breathing tube, so they drown. And palm oil is cheap, natural, and biodegradable.
Since the control mechanism is physical, not chemical, there is no way the critters can develop resistance, nor any bad effect on anything else in the biosphere.
Work with Nature, not against her.