Just to clarify Rachel Carsons impact on aerial application and the over all accuracy of her fear mongering it is my opinion she was an early start of the infestation of the " Tree hugger " mentality.
We used DDT mixed in fuel oil as the carrier at the rate of .05 % DDT to fuel oil.
It was virtually 100 % effective in killing the adult mosquitoes when we sprayed a given area to control them.....there was never to my knowledge any documented case of the mosquito population showing immunity to DDT....it killed them period.
However the authorities bought into Rachel's ranting about the dangers of DDT and it was banned for aerial application......we of course have no idea how many lives she saved, but we do know that millions have died from malaria because no one has come up with a method of controlling them that replaced DDT.
DDT is a chlorinated hydrocarbon with a relatively high LD50 and it can build up in mammals fat tissues with a very long life span.
I handled thousands of gallons of the stuff and applied it from airplanes for years and so far I have not seen any evidence it has affected me in the least.
Malaria is a frightening disease and I am fortunate I never contracted it during my many, many contracts all over Africa...some of our crew members did though and one died.