If you're intending to use natural methods to get rid of potato bugs in your garden, then the best bet for you to get rid of them is to introduce the natural enemy of the creature into your own garden. Hence, you should look at introducing ladybirds, lacewings, stink bugs and some species of spiders into your garden. These insects should not be able to affect your garden's health, but will undoubtedly be able to get rid of the troublesome potato bugs in your garden. These predators that are introduced into your gardens will simply prey on the potato bugs.
You can also use botanicals to get rid of the bug, with ease. This is a more natural way of getting rid of the bugs, as opposed to pesticides. So say for instance you are suffering from an infestation - rotenone is a botanical that comes from the roots of certain kinds of plants. Once you introduce this to your garden's crops, it will slowly begin to kill off the potato bugs in your garden. Pyrethrum is a more aggressive botanical, however. It can also be combined with rotenone for much faster results.
If you can't make this work, however, then you should use biopesticides in your garden. This is a better alternative to using several kinds of chemicals in the soil of your garden. Biopesticides can't be used in organic farming, however, as they are still technically chemicals. They generally come in the form of a spray, and are incredibly effective at getting rid of potato bugs that have started infesting your crops. You can also place a floating row cover over your potato crops once all of the bugs are gone. This is a way of stopping the infestation from reoccurring in the future.