Ground mosses grow when a lawn thins out due to low vigor, excessive moisture, or excessive shade. Some plant parts might be mistaken as a pest. For example, ferns have reproductive structures called sori on their lower leaf surfaces which look a lot like scale insects. Some other corky outgrowths occur on stems and are perfectly normal for certain plants. In Florida, they are seen on Sweetgum and Winged Elm.
Some plants have other bark characteristics which can be mistaken for problems.
This is by no means an exhaustive list of all of the common instances of mistaken identities. Pay special notice to the section in which certain beneficials are placed beside the harmfuls with which they are often confused. The following are often mistaken for pest damage, but cannot be cured by applying pesticides. Citrus rust mite damage can be controlled, but there is no need to do so under home growing conditions because the damage is superficial. Use physical methods such as hoeing, hand pulling, using monofilament line trimmers.