Bugs n’ things are natural in nature. It becomes a “pest” when the organism competes with our interest and becomes a nuisance, or worse, detrimental to our trees.
The term “Pest” can include insects, weeds, fungi, viruses, and bacterium. Hence, a “Pesticide” is anything that helps to control these pests.
Not all pests require pesticides. The goal of pest and disease management is not to eradicate everything entirely, but to suppress it to an acceptable level.