Why can't we just kill all the mosquitoes?

What's the deadliest animal in the world? A shark? A bear? Nope, it's the mosquito. I know it may sound funny such a tiny thing being so deadly, but since mosquitoes spread so many deadly diseases very rapidly, they have killed more humans than any other animal. I believe it is our job as a species, or humankind or whatever you want to put it as, to eliminate all threads to humanity and living as the best we can or move towards doing so. We have a moral obligation to do that. Now, since mosquitoes kill so many people, why don't we just kill them all? Make them go extinct? I think we should unban DDT because a lot of the studies saying it is dangerous have been debunked. Banning DDT has killed millions of people in the third world because they would get malaria from otherwise unkilled mosquitoes. Let's just spray that **** everywhere until all the mosquitoes are gone. No more malaria, no more zika. No more any of that! Let's save billions of lives. And those kids that I see pictures of, with half their head because of the Zika virus. My heart goes out to them. Their entire future is ruined. I want to prevent that forever. Let's do this. Kill all the mosquitoes.