The number one pest for cannabis flowers are spider mites. They are extremely destructive and sap massive amounts of energy from the plant. The growing plant that’s infested will often suffer. Final flowers also suffer. The effects add up to a multifaceted recipe for disaster. Resin concentration, potency, effectiveness and yield will be lower. Overall appearance of the flower will be less attractive.
You can tell if a flower was infested while growing. Look closely at the leaf material still on the flower that wasn’t trimmed off. Look for spotting on the leaf blades like little pinholes blanketing the leaf. If the flowers were trimmed closely and no leaves are readily viewable, break a flower open and examine a leaf inside that the trimmers couldn’t get to.
If the leaves have yellowed out it’s more difficult to see mite damage. In that case, it helps to examine the leaves’ undersides which also have distinct signs. Look for egg clusters on the undersides. They are really small, smaller than the size of a grain of salt. If the plant was mite infested you’ll see white granule-type formations there. These are mite eggs, not “crystals”. If you see them on your flowers, then you’re smoking them.