Some strains like landace indicas e.g. Hindu Kush, Afghan Kush seem naturally resistant to insects and diseases at least in my outdoor San Diego plot. Others I've grown like Wiz Khalifa or GG4 in my 2018 grow are less so. BUT I grow trees that leave plenty for us all without the worries. Except to keep the occasional cocoon from some critter or other out of my trim. A big difference between gardening for veggies compared to cannabis is the size of the plant and amount of product at harvest. Trimming an 8 footer will reinforce that notion. Constant sunshine and dry conditions all Summer are a great help to this scheme, as well as the outside grow with proper spacing. If you are fighting pests and disease you have my sympathies. But so far here in So. Cal. no worries.