When greens talk about proper use of DDT and roundup, I support them, externalities do exist after all, but many if not most want to ban its use altogether.
I hear people who want a total ban on the use of DDT and Roundup, who justify such by citing super bugs or super weeds. Super bugs or super weeds are just bugs/weeds resistant to the pesticide or herbicide that they want banned anyway so what what is the big deal?
Part this has to do with optimism verses pessimism if one is optimistic about a richer better future he says lets maximize the befits from roundup and DDT now when we need them more. Future generations will have better ways to deal with bugs and weeds. Even if they don;t they will surely have better means of dealing with other problems leaving them able to invest more of their energy on growing food.
BTW resistance usually costs energy to an organism and so if we stopped using DDT or Roundup the resistance would slowly be lost.