PESTICIDES: THE SOLUTION TO ONE PROBLEM - AND THE CAUSE OF MANY...by David Gharairi, Williamsville, NYSince the beginning of agriculture, people have looked for methods to compete with pests. Pests may include insects, fungi, weeds, birds and rodents. Pests destroy our way of life for their own survival. Pests have destroyed crops, stung and bitten people and transmitted diseases including malaria and typhus. It was not until the 1800's that farmers began using pesticides.Pesticide development was closely associated with wartime research. Before World War II, there were only 30 types of pesticides used. Today there are over 50,000 pesticides and 1.8 billion kilograms of these chemicals are used each year around the world. DDT was originally developed to protect soldiers from disease-transmitting flies and mosquitoes. DDT was then also used in the United States to protect crops. Later, the "miracle chemical," DDT, was banned due to health risks, and because it killed more than just pests. For example, DDT softened bird egg shells so that they would not hatch. DDT also caused many reproductive problems in animals.Pesticides are not effective for the long run. In time, they will destroy the ecosystem because of biological magnification, which is the increasing concentration of a pollutant in organisms at higher trophic levels (feeding levels). For example, if the pesticide was concentrated in produce (greens) and some animals ate the produce, the chemical would become more potent in those animals. The concentration would become even higher in the predator that ate those herbivores. A scenario: the produce is contaminated with pesticides. The mice eat the produce and owl eats the mice. In this case, the owl is at the top of the food chain, so the owl would be the first to die off. Another scenario: the phytoplankton have been contaminated with pesticides. A man eats ten fish; those ten fish ate 100 dragonflies; those 100 dragonflies ate 1,000 aquatic insect larvae, those 1,000 aquatic insect larvae ate 10,000 phytoplankton (plant plankton). The man has been contaminated in the most concentrated dosage - 10,000 contaminated phytoplankton of pesticide. Pesticides do not pass out of the system, but stay in the fatty tissue of the animal and the tissue of plants.There are four problems with chemical pesticides because they are non-specific. First, they kill more than just the pest, they kill the insect's natural predators. Second, insects can easily mutate to resist poisons. Third, the chemicals are harmful to humans. And last, insects will make a greater comeback after pesticides are applied, because their predators have been killed off. Insects develop a resistance to the chemical because they consume only small amounts, have a short life span and reproduce quickly.Health risks for humans include birth defects, genetic damage and other reproducive problems. The chemicals may interfere with the functioning of the nervous or respiratory systems. Some pesticides that cause these problems are called organochlorides (like DDT) and some are banned. Organophosphates are widely used today, instead, which are not as dangerous as organochlorides.The long-term solutions to pest control are not always fast or easy. Nonbiological methods include traps, screens and electric bug zappers, which are not specific and kill the pests along with the helpful insects. Biological methods are very specific and more effective. These are the methods that should be used in place of pesticides. (Unfortunately, pesticides are much faster and cheaper.) Introducing a pest's natural enemy is one biological method. Sometimes parasites (such as fungi, insect larvae or bacteria) are used to wipe out pests. Ladybugs are predators that control aphids and scale insects. Also, just recently a larvacide called BT (in the form of white blocks) was developed to kill mosquito larvae. Insect hormones can also be used to repel insects or lure them into traps. A farmer would be reluctant to try one of these methods because not only are pesticides faster and easier, but he would lose many crops the first year. A predator/prey integration would take a little time but, in the long run, the farmer would have more crops and a cleaner, healthier environment. ^