To insist that insects—good, bad, or indifferent—should be banished from the garden is to begin a skirmish that leads to incessant warfare, a warfare that is unwise, unwinnable, and virtually unnecessary.
—Eric Grissell, from Insects and Gardens (Timber Press, 2001)

If only aphids, slugs, and cutworms were as dreadful as their names sound, and honeybees, butterflies, and earthworms were as beautiful, or dutiful, as their Saturday morning cartoon caricatures. Then it would be easy to distinguish between which creatures are beneficial for your garden and which are truly pests. In reality, however, bugs are much more complicated. Though this much we can be sure of: Insects and other small terrestrial and airborne creatures play a vital role in any garden’s overall composition.

The arrival of nonnative insect species makes it even harder to know which creatures are “good” or “bad” in a particular setting. And as with many other territorial battles, you can choose between two paths: Wage all-out war no matter what the collateral damage, or know the issues on the ground and engage in only the occasional, well-aimed assassination. To help you decide, here’s a quick primer on four common denizens of western Oregon’s gardens.