In Mother Nature’s eyes all insects are created equal. Gardeners generally consider insects to be beneficial when they prey on plant “pests”. For instance ladybugs and their larvae eat aphids, and so in our eyes ladybugs are beneficial, aphids are not.
These sentiments arise from a misunderstanding of natural processes. A healthy plant may be nibbled on, but it will not be infested with insects or microbes. These only seriously attack nutrient deficient plants, and within an ecological context that is highly beneficial - to the plant species that remain strong, and also to the species that depend on the healthy plant as food, such as larger animals and humans.
When we import predaceous insects in response to a “pest” problem we actually use them as a pesticide. When their food source is exhausted they will either die or move on.
In a healthy, biodiverse garden it should never be necessary to import “beneficial” insects, because their populations will already be established. This also means that we need to tolerate a few “pests”, because without them their predators would have no food. The greater the plant diversity, the greater the insect diversity - and that is beneficial to the ecosystem as a whole.
We go much deeper into this topic in our online course, which you can discover here: