Since mosquitoes are soft-bodied insects the garlic juice can be very toxic to them in increased concentrations. The juice does not harm humans, pets or plants, but to mosquitoes it can be deadly. The odor of garlic chases them away for as long as they can detect the odor. The odor of sprayed garlic juice becomes undetectable to humans within minutes, but mosquitoes can detect odor as much as 10,000 times better than a human. So even though you can't smell the garlic, they can and they will stay away from the sprayed area for up to a month or longer. If the mosquitoes aren't in your yard, they can't get into your house.
Mosquito Barrier is a three pronged attack:
(1) It kills the adult mosquitoes.
(2) The garlic coated plants keep mosquitoes out of the area.