What Is A Pesticide?

Few words bring up such consternation as “pesticides”. Some folks are vehemently against them and even go so far as to protest the use of pesticides.
What is a pesticide? There are a variety of answers, but the best one I know of is anything that kills, mitigates, repels or inhibits a pest. Pests can be any unwanted critter or pathogen in your home, landscape, agricultural operation, and even unwanted in the surrounding environs.
There are several kinds of pests and sub-categories of pesticides. If my pests are insects, I use an insecticide. If weeds are my problem, I use an herbicide. Mites? Get a miticide. Mice or rats? Use a rodenticide.
So let’s describe some kinds of pesticides. First is chemical. Chemical insecticides would include natural and man-made compounds. In addition to the obvious chemical compounds, one should include soaps, nicotine, carbaryl (the active ingredient in Sevin), and 2,4-D to kill broadleaf weeds.
We can control pests mechanically. Think of your garden hoe, a mousetrap, disking a field, and even your fly-swatter.
Less obvious is legal pest control measures. Most everyone is unaware that we live under a fire ant quarantine. This quarantine seeks to control the spread of fire ants into counties that still do not have them. Another excellent legal effort is with the USDA’s Animal and Plant Health Inspection Service (APHIS). This is an agency responsible for protecting animal health, animal welfare, and plant health. They do so with inspections as well as the investigation and enforcement of alleged violations relating to animal and plant issues under APHIS’ jurisdiction.
Cultural methods such as crop rotation and prescribed fire are excellent at controlling pests. Crop rotation should still be practiced around here in home gardens where vegetable species are planted in different locations during subsequent years. Fire (and I’m talking about a prescribed fires) is an excellent, but often misunderstood tool that foresters and ranchers utilize to control undesirable vegetation as well as encourage preferred and native plant species.
Prescribed fire (in contrast to a wild-fire) is such a tremendous instrument that the public isn’t aware of, that its discussion warrants full attention in a later article.
Biological or natural pesticides would include Bacillus thuringiensis (or Bt), and the phorid fly. Use of these biological pesticides can also be somewhat controversial. The phorid fly preys on fire ants. The release of them some years ago in our part of the world caused some raised eyebrows as folks wondered what other native insects it may impact.
Bt is a bacteria that causes death to any insect larvae that ingests it. Applied to your garden, you can thwart all manner of caterpillars. Used in your ponds or other standing water, you can stop the development of the mosquito “wigglers”.
Natural and biological pesticides control pests using things found in nature, or man-made versions of things found in nature. Nicotine from tobacco (and other related plants) is an excellent toxin that can be used against insects. Neonicotinoids are a relatively new class of insecticides chemically related to nicotine. The name literally means “new nicotine-like insecticides”.
Does that cover them all? Not by a long shot. The National Pesticide Information Center lists the following additional pesticides.
Algaecides are used for killing and/or slowing the growth of algae. Antimicrobials control germs and microbes such as bacteria and viruses.
Desiccants are used to dry up living plant tissues. Defoliants cause plants to drop their leaves.
Disinfectants control germs and microbes such as bacteria and viruses.
Insect Growth Regulators disrupt the growth and reproduction of insects. Plant Growth Regulators are used to alter the growth of plants. For example, they may induce or delay flowering.
Molluscicides are designed to control slugs, snails and other mollusks. Mothballs kill fabric pests by fumigation in sealed containers.
Ovicides are used to control eggs of insects and mites. Pheromones are biologically active chemicals used to attract insects or disrupt their mating behavior.
Repellents are designed to repel unwanted pests, often by taste or smell. Synergists make certain pesticides more effective, but they are not effective when used alone.
Wood Preservatives are used to make wood resistant to insects, fungus and other pests. Fungicides are used to control fungal problems like molds and mildew.
One of the responsibilities in my job is to better equip the consumer to ask questions about what they are purchasing and what practices they are truly willing to employ as they seek to control pests. Understanding all the pesticides that are used in the home, landscape and for food production can be a challenge.
On Tuesday, Aug 15 from 12 noon to 1 pm, our office will be hosting a free seminar on controlling pests in the home and garden. Bring your lunch and join the Master Gardeners as they host this educational seminar.


Cary Sims
Cary Sims
Cary Sims is the County Extension Agent for agriculture and natural resources for Angelina County. His email address is cw-sims@tamu.edu

Educational programs of the Texas AgriLife Extension Service are open to all people without regard to race, color, sex, disability, religion, age, or national origin.

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