In Sweden, they use helicopters to bomb the mosquitoes with the pesticide Vectobac G.
I'm absolutely not an expert but I was under the general impression that DDT is no longer permitted because it's not safe.
This is usually brought up as a weird rallying point for people with an ax to grind with Silent Spring, nevermind the very real effects of DDT and nevermind the exemptions explicitly dealing with the objections raised.