There are ways to grow plants without resorting to using chemical poisons that could threaten not only you and your family, but other benign creatures such as butterflies, bees, even pets.
In some instances, a mechanical means can help banish bad bugs. This would include hand picking the insects off the plants, or putting up a barrier, like a cardboard circle around the stem. A rather gruesome mechanical option is crushed eggshells sprinkled around the base of susceptible plants. The sharp edges cut the soft bellies of insects like slugs.
Another method would be baiting, such as putting a saucer full of beer out to attract slugs away from your hostas. They seek out the source of the yeasty smell and drown in the saucer.
Biological means vary, as to which pest you are trying to beat. They include:
Bt, which is short for Bacillus thuringiensis. Bt is a soil bacteria that occurs naturally. It is very useful for controlling leaf eating caterpillars and beetles.
Diatamaceous earth, a natural material that kills pests by dehydration. This is lethal to aphids, leafhoppers, snails and slugs. However, after a heavy rain, it will need to be reapplied.
Insecticidal soap helps to control aphids, mites and other fluid sucking insects. This needs to be applied several days apart for 3 or so applications to break the life cycle of the insects. Be sure to apply to upper and lower surfaces of the leaves.
You can find organic pest control at Madison area greenhouses such as Kleins, 3758 East Washington Avenue, Madison and on the west side, Johannsens, located at 2600 West Beltline Highway in Madison.