Mosquitoes harder to control as some developing resistance to common insecticide, NC researcher saysTiger mosquitoes in Wake County are developing resistance to pyrethroids, a common insecticide used in residential and commercial mosquito control programs, according to researchers at North Carolina State University. Tiger mosquitoes in Wake County are developing resistance to pyrethroids, a common insecticide used in residential and commercial mosquito control programs, according to researchers at North Carolina State University. Tiger mosquitoes in Wake County are developing resistance to pyrethroids, a common insecticide used in residential and commercial mosquito control programs, according to researchers at North Carolina State University. Tiger mosquitoes in Wake County are developing resistance to pyrethroids, a common insecticide used in residential and commercial mosquito control programs, according to researchers at North Carolina State University. Tiger mosquitoes in Wake County are developing resistance to pyrethroids, a common insecticide used in residential and commercial mosquito control programs, according to researchers at North Carolina State University.