As early as 10,000 BC the human race understood the importance of controlling weeds in an agricultural setting. Weed control began with simple hand weeding, but proved to be extremely inefficient. Innovative means of control were discovered, but many of them were ahead of their time and did not become common practice. Thousands of years later, in 1000 BC, animals were finally domesticated and utilized as a means to improve cropping fields. It was not until the 20th century that pest control practices were modified and began to advance at a rapid pace. Mechanical tools emerged in the 1920s, followed by biological controls in the 1930s and chemical controls in the 1940s. Although chemicals are effective in eradicating countless pests, they have progressively gained scrutiny and speculation over time.
Pesticides became predominant practice in order to control nuisances in the mid20th century. In 2012 the EPA estimated 5.2 billion pounds of pesticides were used worldwide, forty percent of which were herbicides (Pesticide News Story, 2011). History testifies of the use of chemicals to control weeds, but it has only been in recent years that we have begun to understand and evaluate their impacts.
Pesticide use dates back as far as 1000 BC when the Greek poet, Homer, described the use of sulfur to deter pests (Some Pesticides, 2013). Since that time we have found other records that prove use and experimentation with chemical compounds. They include amurca, salts (including copper sulfate and sodium arsenate), and hemlock and lupine flowers. As time progressed, so did man’s ability to utilize organic chemicals. In 1904 petroleum oils were used to control weeds along irrigation ditches, in 1906 carbon bisulfide was used to control Canada Thistle and bindweed, in the 1920s sodium chlorate and arsenic trichloride (also known as ‘Kill Morning Glory’) was used to control bindweed, and in the 1930s sulfuric acid was used to control unwanted vegetation. It was not until the 1940s that the first successful synthetic herbicide was discovered. R. Pokorny, a chemist specialized in synthetic compounds, created 2,4-D. In small doses 2,4-D imitates indole acetic acid, or IAA, a growth-regulating hormone naturally found in plants. When increased in concentration IAA has the ability to act as a general herbicide. This monumental discovery led to the invention of several general and selective herbicides by the end of the 1950s, which were heavily used. However, we did not fully understand the consequences of their uses and it has now become controversial whether the benefits of herbicides outweigh the negative aspects.
Herbicides have impacted our world and our lives in many diverse ways and we have only recently begun to fully understand them. Every day we are searching for answers as to how they impact our ever-changing world, why it is important to understand them, and how we can resolve any negative impacts they have. The largest problems we deal with are...