Not long ago, gardeners seemed to spend as much time controlling pests as they did any other garden activity. Malathion, diazinon, Dursban and chlordane were about as popular as marigolds, dianthus, dahlias and chrysanthemum.
It's nice to see that gardeners have evolved a much more laissez-faire approach to the six-legged inhabitants that share our gardens. Maybe gardeners today are just too busy, or maybe they're just not paying as close of attention as they used to, but there seems to be a lot less spraying, dusting, baiting and generalized killing going on in gardens nowadays.
But mostly I think that gardeners are now realizing that in a healthy, well-managed garden, some pests are best controlled by letting things be, by letting species interactions run their course. After all, this is the basis of biological pest control.
Biological control agents are often referred to as natural enemies or simply as beneficials. Every day, in every garden, there is a continual interaction between pests and their predators, parasites and pathogens. Most of this interaction we, as gardeners, don't participate in and may not even be aware of.