Organic Pest Control

What does organic mean?

The term organic can be confusing and is often misused.

In the purest sense of the word, organic is defined as any substance containing the element carbon. Carbon is present in all living matter, so, simply put, organic substances are derived from living matter.

In horticultural terms, organic is defined as a method of growing or maintaining ornamental or food plants (ornamental or food) without the aid or application of (human-made) synthetic chemicals (fertilizers, pesticides, hormones, etc.). Many people think of organic gardening as nature’s recycling program.

The term, “organic gardening”, is of fairly recent origin. The word, organic, was first used to describe the natural method of gardening and farming in 1942. The term “organic farming” was first used in a 1940 publication. “Organic” gardening or farming is a philosophy, and components of it have been practiced for centuries (from Gates, J.P. 1989 [mimeo]: “Organic gardening,” Agri-Topics, National Agricultural Library, USDA).

Most practitioners of organic farming concentrate on preparing soil with a high organic content using materials such as fertilizers and amendments that are deemed to be of natural origin. Practitioners contend that most pests are secondary problems of crops, and are symptoms of unhealthy plants. This philosophy holds that plants grown organically have fewer pest problems (from A Review of Organic and Other Alternative Methods for Fire Ant Control).


Chemicals are either natural or synthetic. Natural chemicals exist in the environment, often produced by plants (e.g., botanical insecticides like pyrethrins) or fermentation products from mico-organisms (e.g., spinosad), or “near organic insecticides” that do not contain carbon (e.g., silica dioxide in diatomaceous earth or D.E.). Synthetic chemicals are made using chemical reactions and introduced by humans. Insecticidal soap is made from a reaction of potassium with long-chained fatty acid or carbon molecules), both of natural origin (as is petroleum) but synthesised from a chemical reaction.  Many people mistakenly assume that “natural, organic chemicals” are less toxic than synthetic chemicals. Not true, since there are many poisons that come from naturally existing plants and animals that are more toxic than some synthetic chemicals (e.g., nicotine sulfate). So, chemical toxicity is not an accurate measure of “organic.”

The chief reason for employing organic practices in horticulture is perceived positive impact on the environment. Organic substances (those with carbon atoms) can be broken down by micro-organisms (as in composting), reactions with other chemicals, or by light. Many inorganic substances such as boric acid cannot be broken down by other living things. Many naturally occurring organic pesticides, like pyrethrins, biodegrade faster rapidly inn the environment.

In food and livestock production, the term, organic, is now defined by laws at both the state and national levels (see links below). Programs list specific allowable products that can be used, such as insecticidal soap. Product produced using organically can not be sold using the term on their labels unless the producer or manufacturer is certified. However, in the turfgrass and ornamental landscape (non-food crops) , standards do not apply and the debate continues as to what is or is not “organic” (used in quotes to represent this uncertainty).

Organic Practices and IPM

Integrated pest management (IPM) is a philosophy that urges a systems approach to manipulate pest densities. Programs based on this philosophy rely on field scouting or monitoring efforts and historical information upon which to make management decisions. All methods for manipulating pest populations are considered, and management programs use a combination of non-chemical (cultural, physical and mechanical), biological,  and chemical methods over time to achieve management objectives. These programs strive to be 1) the least environmentally destructive, 2) the most effective for manipulating pest densities, and 3) the most cost effective.

Methods defined as “organic” certainly are valid options for implementation, and some are “least-toxic” options. However, IPM programs do not eliminate the potential for using methods and materials not defined as organic. If fact, for serious pest outbreaks, having powerful insecticide products in our arsenal is a necessity.