Beetles are the group of insects with the largest number of known species. They are classified in the order Coleoptera, which contains more described species than in any other order in the animal kingdom, constituting about 25% of all known life forms. About 40% of all described insect species are beetles and new species are frequently discovered. Beetles can be found in almost all habitats, but are not known to occur in the sea or in the polar regions. They often feed on plants and fungi, break down animal and plant debris, and eat other invertebrates. Some species are prey of various animals including birds and mammals. Certain species are agricultural pests, while other species of beetles are important controls of agricultural pests.
Cockroaches are among the most unwanted pests of households and commercial establishments. Not only is their mere presence a nuisance, but they are known to be capable of carrying many common disease pathogens as well as causing allergic reactions in many people. Of the approximately 4,000 living species of cockroaches in the world, about 70 occur in the United States.
Non-biting flies are one of the most offensive pest groups because they are not only nuisance pest, but many are also important in disease transmission. Flies feed on a variety of food materials, but most of those of structural importance develop in either fermenting or decaying organic matter, although a few are parasitic on other animals. You can control flies with an insect plasma light trap, but fly control is often quite challenging because their larval developmental site(s) must usually be located and eliminated for success. These sites can be quite a distance from where the adults are nuisances. See below for a chart of pest flies.
This is a catch-all group for those pests which invade homes from time to time. Although some may cause damage indoors, such as crickets, they do not enter a structure for this purpose. They are typically nuisance pests which cannot survive for long indoors.
Information from the National Pest Management Association: http://www.npmapestworld.org/pestPedia/