Are We the Pests We’re Getting Rid of?

A common view of pesticides, herbicides, and fungicides is that, after we apply them, they’re effective for a certain length of time, sooner or later lose their effectiveness, and then somehow magically disappear without a trace. Although it is true that the effective shelf-life of these products is limited, their magical disappearance is not. Instead, they and their chemical components persist, often with disastrous consequences for our environment, for plant and animal life, and for human health.

How each product impacts the environment varies, but the damage often starts with a product’s application and persists long after its effective shelf-life has ended, as the following lists suggests:

• Application. Pesticides, herbicides, and fungicides applied through spraying (whether through aerial spraying, spraying from aerosol cans, or spraying from pumps) either are evaporated or persist in the air, where they are inhaled by animals and people. Although spraying typically targets a particular pest, well over 90% of pesticides and herbicides reach non-targeted life forms.
• Targeting. While some of these products target specific pests, such as specific molds or specific agents causing disease in plants, many do not. Pollinators are often unintended targets of these products – and pollinators are essential to sustainable ecosystems. And rat poisons often target not only rats and mice, but also animals such as squirrels, chipmunks, possum, cats, dogs, and even humans.
• Dissipation. Weather conditions, and particularly precipitation, spread these products throughout the soil and into the water.
• Persistence. Chemical agents persist on plants and then can be found in products manufactured from plants. Consumers of these plants also consume these chemicals, and consumers of products manufactured from these plants likewise consume the chemicals. The most notable of these is glyphosate, the active ingredient of Roundup. Although safety levels for food products are regulated by the Environmental Protection Administration and most recently were set in 2020 (under the Trump administration), scientists and environmental activists have contended that the levels are far too low. A 2018 study found glyphosate in almost all sampled foods that contained non-organic oats, and about a third of foods that contained organic oats. Along with its undesirable impact on plant and animal life, a recent study suggests that there is a link between glyphosate and some forms of cancer (in this case non-Hodgkin Lymphoma). Links between glyphosate and other health and reproductive issues remain under investigation.
• Effectiveness. The very effectiveness of pesticides in some cases results in environmental damage. By eliminating their food source, pesticides lead to starvation or to undesirable changes in the behavior of predator animals as they seek new food sources.
• Long-term ineffectiveness. Repeated use of some fungicides or herbicides leads to immunity in their target populations. This often results in application of larger volumes of the fungicide or herbicide or to the use of a newer product whose impact is not fully known.

To limit our exposure to or our own use of pesticides:

• Buy organic produce when a choice is available. A 2018 study found that the risk of cancer declined significantly among consumers of organic food, with a strong inverse relationship between the proportion of organic food consumed and the incidence of cancer.
• Consider whether a pest is really a pest. In many cases, we can coexist with rather than eliminate wildlife such as squirrels, chipmunks, possum, bats, and rabbits. In other cases, creatures that we consider pests (such as spiders, slugs, and snails) play a useful role in maintaining the equilibrium of ecosystems; we may find it beneficial to simply leave them alone.
• Consider relocation rather than extermination. Rather than poisoning vermin, consider disposing of them in a human manner, by trapping them in cages and relocating them to forested areas. Rather than killing spiders (whose presence in your home indicates that your home has a large enough insect population to sustain them), consider moving them elsewhere or eliminating the insect population that sustains them.
• Adopt a non-toxic biopesticide to eliminate insects or other pests. Biopesticides are pesticides derived from natural substances that typically do not involve the collateral damage of manufactured pesticides. Some of these include:
  • Diatomaceous earth, a dust-like substance formed from the fossil remains of diatoms. It kills insects by eroding the protective layer on their skin, leading to dehydration and death. Among other things, it’s very effective in getting rid of ants. Available at garden centers, it must be reapplied after rain or heavy watering.
  • Neem oil, an oil harvested from the seeds and leaves of the neem tree. It disrupts the life cycle of many insects and is also effective against some forms of mildew and other fungus. It is also non-toxic to pets, wildlife, birds, fish, bees, butterflies, and ladybugs and doesn’t pollute the ground water. It should be applied in the morning or evening so that the combination of sun and oil cannot burn foliage.
  • Vinegar, which kills plants when sprayed on them. When combined with salt, it kills plants and prevents them from coming back. It is not a selective biopesticide, however: it kills any plant on which it is sprayed.
  • Boiling water, which kills plants when poured on them. Like vinegar, you should only use it for weeds that you wish to eliminate.
• Repel rather than exterminate. Some natural substances will drive pests away rather than kill them. Some of these include:
  • Peppermint, thyme, or rosemary oil, which repels such pests as flies, fleas, mosquitoes, caterpillars, aphids, ants, beetles, spiders, ticks, and roaches. It is administered by mixing with water and spraying around a garden.
  • Peppermint oil can be used in additional ways. It can also be sprayed around windows, doors, and other areas to repel spiders, placed in a shallow dish of water in a room to repel mosquitoes, and dipped in cotton balls and placed around a home to repel rats, mice, squirrels, and rabbits.

With some investigation, it should be possible for us as consumers to eliminate the use of toxic pesticides, herbicides, and fungicides, and to find a suitable alternative that will eliminate or repel pests while preserving our common home.