Substitute Natural for Chemical Biocides: Part 1

The products we use to try to rid our house and yards of pests comprised a significant source of hazardous materials. Known collectively as biocides, these substances include insecticides, pesticides, rodenticides, fungicides, and herbicides. They are meant to kill living organisms; in fact, the suffix “cide” comes from the Latin verb meaning “to kill”.

There are a number of very good reasons why we should use as few chemical biocides as possible:

• They harm creatures other than those they are intended to kill. Once used, a biocide settles into the soil, where it remains or is washed into a body of water. In either case, it is absorbed by organisms living in the soil or mud. Through a process known as biological magnification, the biocide accumulates and is concentrated at progressively higher levels in the food chain. Predators accumulate a larger amount than their prey, and the effect on birds and fish may be lethal. Some commonly used chemical biocides are suspected of causing cancer and birth defects and damaging the kidneys, liver, nervous systems, and immune systems in humans. Even the chemicals used in some flea collar have been found to cause permanent nerve damage, cancer, and birth defects in cats and dogs.

• Biocides end up in our food supply. More than one hundred different pesticides have been detected on commonly eaten fruits and vegetables.

• Biocides may exacerbate the problem they were designed to eradicate. By altering the natural processes that determine which insects in a population will survive, biocides spur the development of resistant species. If all but 5% of the mosquito population in an area is killed by an insecticide, the ones that survive are the most resistant individuals, and they are the ones that will produce the succeeding generations. More than four hundred insect and mite species are known to be resistant to pesticides, and some “super weeds” are totally resistant to certain herbicides.

• Biocides have also created further problems by destroying beneficial insects, te natural enemies of the intended target, leaving the pest to breed unchallenged. Thus, spraying an infested crop might kill 90% of the pests – but it also kills the insects that eat the pests. With their food abundant and their predators rare, the remaining pest recover faster than their enemies, whose prey is now scarce and harder to locate.

• Biocides are overused. American households annually use over 60 million pounds (27 million kg) of toxic chemical biocides; agricultural uses account for another 460 million pounds (209 million kg).

• The entire process of insecticide development may be self-defeating. Despite the billions of pounds (and dollars) used to attempt to eradicate pests, crop loss to insect and weed pests has actually grown. According to Department of Agriculture figures, 32% of crops were lost to pests in 1945; forty year later, such losses had increased to 37%.