Pesticide Resistance

How has the increased use of pesticides in the US affected crop output and pest populations?
What enables pest populations to increase/adapt rapidly?
How do these new pest populations affect pesticide usage?
Are there any alternatives/solutions to the pesticide resistance problem?

Conventional farmers in the U.S. regularly rely on pesticides and herbicides. Additionally, they often use agricultural methods such as monoculture (the cultivation of a single crop) and genetically identical crops to maximize output. These methods of agriculture have an effect on the number and strength of pests. There has been a significant increase in the proportion of crops lost to pests since the beginning of the Agricultural Revolution in the 1950's, and a study conducted by the University of Vermont concluded that pesticide resistance has cost the U.S. $1,400,000,000 since then.

Pests, like many other things in nature, have the ability to adapt to their surroundings. Most weed and insect pests have short life cycles, a wide geographic range, and large populations. Consequently, there is substantial genetic diversity found in pest populations. When these populations are sprayed with the same toxic chemical, a few individuals are not killed because they are genetically resistant. These individuals survive to reproduce, quickly resulting in localized resistant populations which then spread. Consequently, higher and higher doses of pesticides are needed to kill pests, thus creating the need for new, stronger pesticides to be developed. Then the cycle begins again, resulting in increasing costs, increasing amounts of chemical use, and an ever-decreasing effectiveness of products. This cycle is aptly dubbed the "pesticide treadmill." This is clearly not a sustainable agricultural practice.

The process of developing and applying pesticides is an unending problematic chain that continually increases the risks to human and environmental health. For example, though banned in many European countries, the pesticide atrazine is becoming more widespread in the U.S. While a maximum contaminant level has been set by the EPA, atrazine leaches into groundwater and was the second most frequently detected pesticide in EPA's National Survey of Pesticides in Drinking Water Wells. EPA's Pesticides in Ground Water Database detected atrazine at concentrations above the maximum contaminant level in ground water in several states

There are many alternatives to chemical pest control. Pest control by promoting natural enemies has been found to be effective. Genetic control or breeding disease-resistant varieties of plants can also be done. Also, as one case study in Pennsylvania showed, some soil management practices, such as organic farming rotations, can reduce the need for pesticides, thus preventing pesticide resistance.

To read more about pesticide resistence, please visit the following sites:

http://www.epa.gov/fedrgstr/EPA-PEST/2000/May/Day-10/p11147.htm
http://paipm.cas.psu.edu/NewsReleases/NRholowid.html