Supporting native diversity in plants and wildlife is the foundation of a sustainable yard. To promote a healthy, diverse ecosystem introduce insects, such as ladybugs, to eliminate harmful bugs like aphids, white flies, spider mites and mealy bugs. Ladybugs can be purchased as adults at your local nursery and can simply be released into your garden.
Another large, beneficial insect is the notorious praying mantis. Unlike ladybugs, these guys need to be purchased as eggs and placed gently into your shrubbery. When they hatch they will eat beetles, flies, and aphids. This rare predator is an interesting and fun insect to have in the garden.
Like most beneficial insects, Spiders do not eat plants and trap many harmful bugs in their elaborate webs. Conversely, jumping spiders and other small spiders do not build webs but attack bad insects on the ground. These types of spiders can kill those pesky beetles eating your prize roses. So if you can stand the sight of them, put some spiders in your flowerbeds!
In order to keep these beneficial bugs in your landscape you will need to introduce different varieties of plants that attract them. Beneficial insects have a predisposition towards plants like marigolds, dill, phlox, butterfly weed, etc. If you introduce some of these plants, your good insects will not leave looking for a better home. Also, make sure you encourage a diverse wildlife population by landscaping with natural plants, supplying adequate food and water, and providing a variety of shelter areas.