I don't spray, so I don't know. I would think, though, that the chemical packaging would have some type of spray schedule for it. Like, "at time of bloom and every 3 weeks after..." Hope you can find an answer
Depends on where you are. You can do a spring coat of dormant oil as long as the leaves haven't really popped out. After the leaves start coming out, you have to use something else though. I just do sticky red ball traps later in spring.