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Pest: Function: noun Inflected Form(s): -s Usage: often attributive Etymology: Middle French peste,from Latin pestis 1 : an epidemic disease associated with high mortality; specifically : PLAGUE 2 :something resembling a pest especially in destructiveness or noxiousness; especially : a plant or animal detrimental to man or to his interests. 3 : one that pesters or annoys: NUISANCE <gave the greatest encouragement to those pests of society, mercenary informers — Edmund Burke> Source:Webster’s Third New International Dictionary, Unabridged. Merriam-Webster, 2002. http://unabridged.merriam-webster.com (3 Aug. 2010).
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The term “pest” covers a wide range of subject matter. Here, we are chiefly interested in Webster’s second and third definitions, i.e., one that pesters or annoys, or one that resembles such. Definition 2 would not be needed except that, in point of fact, our perception of what, exactly, is doing the pestering, and how serious that pestering is, often becomes so complicated that we miss the point and pronounce as pests those animals amongst us that are–in truth–our greatest benefactors.
In other words, we sometimes pronounce as pests those things that merely resemble pests when, in fact, most of the latter are truly beneficial, and even essential to good health and comfort.
RAT SNAKES:
Essentially harmless rat snakes, for example, have many of the anatomical features of truly dangerous snakes. For some, just sighting a snake — any snake — produces a traumatic visual experience. For most, the distinction between beneficial snakes and dangerous ones is not worth learning, since for them “the only good snake is a dead one”. Yet it is a fact that our non-dangerous snakes generally do much more good than harm. Without the rat snakes in our midst (most of whom, thankfully, we never see) we would be hard pressed to keep pest rodents under control, and–because they compete with them for food–a lack of rat snakes can cause our encounters with truly dangerous species of snakes to increase. Rat snakes (an expression typically reserved, in North America, for colubrid snakes whose diets consist mostly, if not exclusively, of rodents like mice and rats) are not dangerous to humans or our large animal pets.
Obviously, if we have pets that are rodents or rodent-sized, including miniature dogs, guinea pigs, rabbits, and the like, and we let those pets roam in the yard where they might encounter a rat snake, chances are they will end up in the snake’s belly. And, yes, it is also true that rat snakes have a nasty tendency to snack on birds and their eggs, including chicken eggs, earning them the well-deserved name of “chicken snake.”
Habitat modification, focusing on elimination of rodent harborage and food sources, is the best way to deal with snakes in your environment. Done well, such techniques can make snake encounters practically non-existent, without ever harming any of the rat snakes within the natural environment in which your home and yard is situated. You can keep all such snakes — including venomous species — from coming into your yard from that natural environment, simply by performing a well-conceived habitat modification program conducted fully as a do-it-yourself project.
TACHNIND FLIES:
Similarly, tachinid flies, because they resemble houseflies so perfectly (except for their speedy flights) are loathed along with them, except by those who know how good they are at keeping the most noxious caterpillars known to man under control. Of course, in the case of tachinid flies, it is difficult for most of us to tell them apart from houseflies. Furthermore, they are attracted to sweet liquids and quickly become true pests whenever they interact with man. So, regardless of the benefits they provide us by keeping caterpillars under control, we can be excused for not wanting them around.
In their case, the enlightened individual will continue to take steps to prevent their encroachments on areas where we prepare or consume food, while avoiding the use of broad-band soil toxicants that prevent these flies from pupating in areas subject to noxious caterpillar infestations.
Back to the subject at hand: According to one of the more accepted definitions, a pest is anything
(1) that causes injury to humans; our livestock, poultry, or pets; or our crops, structures, or possessions;
(2) that enters into competition with humans, our domestic animals, or our crops for limited food, feed, or water resources;
(3) or that serves to spread disease to humans, our domestic animals, our crops, structures, or food.
To be specific, according to this same definition, pests can be categorized into four main groupings:
(1) Insects and similar animals, including insects that feed on, cause injury to, or transmit diseases to humans, animals, plants, food, fiber, and structures. Examples are flies, mosquitoes, fleas, termites, aphids, wasps, and beetles, but also can include–under “similar animals”–spiders, millipedes, centipedes, sowbugs, and the like;
(2) live plants or processed plant product (such as structural wood) diseases, specifically harmful conditions that alter a plant’s growth, appearance, or function, including bacteria, fungi, viruses, and nematodes;
(3) weeds (by definition, any live plant that is creating problems due to its behavior and placement) cause harm by spreading contact dermatitis or other annoying conditions such as poison ivy; producing respiratory discomfort via pollen and kindred allergies; competing with non-pest plants for limited resources of food, water, and sunlight; contaminating harvested seeds and grains; harboring, attracting, and nurturing pest insects, mites, vertebrates, or plant diseases; poisoning grazing animals; producing unwanted changes in the palatability of milk and meat; hindering fish growth and development; increasing mosquito breeding and infestations; hindering boating, fishing and swimming activities; clogging irrigation ditches, drainage ditches, and channels; creating transportation hazards by blocking vision, road signs, and crossroads; and by increasing road maintenance costs by damaging roadways with root infiltrations and so on.
(4) vertebrates of all kinds, including mammals, birds, reptiles, amphibians, and fish. When they damage crops or ornamentals, eat or contaminate our foods, prey on our livestock and poultry, soil our buildings, spread disease, damage our possessions and structures, or produce noxious smells or noises, they become serious pests.