Cannabis has a long but relatively recent history, possibly close to 30 million years according to some studies, and for most of this time populations expanded across Eurasia subjected to environmental stresses of different locations from arid deserts to broad-leaved forests to steppe plains. Parasites and even mutualists like various insects, mites, fungi, and bacteria moved with cannabis and some species like the Cannabis Aphid (Phorodon cannabis) or Hemp Russet Mite (Aculops cannabicola) have adapted to it intimately, only ever feeding on it to the exclusion of others. Different pests like various species of fungal Powdery Mildews or viruses such as the Beet Curly Top virus and infamous Hop Latent Viroid are more prolific in host range and can be vectored from nearby plants that host them to cannabis crops. In the last 10 millennia or so, human captivation and subsequent cultivation has exposed this plant to many new environments replete with both conducive factors like beneficial microbes as well as detrimental threats like generalist herbivores.
Through breeding, many traits changed: flowers that were naturally small and sparsely populated by trichomes containing cannabinoids and other secondary metabolites such as esters, terpenes, and phenols exploded in size and trichome density with various chemical permutations.
Understanding cannabis pest mitigation starts with understanding the plant’s history, that pests are naturally occurring organisms, cultivated populations are the product of tumultuous artificial selection pressures, and surviving in nature didn’t require nor bestow adaptations for the level of pest absence as desired in human contexts, so we as growers and enjoyers must not forget the great effort needed to protect and produce acceptable—let alone exceptional—results in yield and potency.
As parasites, cannabis pests benefit from their symbiotic relationship at the expense of the host plant, usually