NOOOOOOOOOOOOOO!!!!!!!! ?If you don't have time to get the fish or if the turtles are too good at eating them, I think mosquito dunks/bits are safe with turtles. They use bacteria to kill the larvae, not a chemical.
Mosquitos can easily get blood from a turtle, especially if your water turtles come out to bask. I've even seen them getting blood from the seams between scutes on a gopher tortoise.