It keeps vampires away, so it makes sense that it can keep unwanted insects away, too. If you are looking for a nontoxic pesticide, look no further than your pantry and try garlic powder. The garlic powder kills aphids in the vegetable garden and can also deter other garden pests from invading -- or from coming into your home. Just liberally sprinkle the place you want to keep bug-free. It's completely safe around humans and pets, and you can find large containers of garlic powder in warehouse club stores.