Merit is a great product to prevent grubs, spring treatment to control fall feeders is how merit works
Mach 2, well Ive never had good luck with it cause certain species of grubs are not effected by it. And its alot cheaper, IMO you get what you pay for.
Many people think they need to control grubs in spring, but they do very little feeding in the spring, ( yes their present ) so a treatment is most likey a wasted treatment and unwarrented.
Dylox is a great product to apply in fall when their feeding, quick knock down but dosent last very long