Why Do We Need Pesticides?

May 25, 2016 | Sustainable Agriculture | 0 comments

The Dirt:

Are you concerned by the toxicity of pesticides used in conventionally grown fruits and vegetables? We did some research and found that the trace levels of pesticide residue that accumulates on fruits and vegetables are significantly below tolerance levels, and are not dangerous to human health. But you may still be asking yourself— why do we even need pesticides? Have you ever wondered how many fruits and vegetables (containing pesticide residue) you could eat before it starts to negatively affect your health? The answer might surprise you…

Strawberries, in particular, have received a very bad reputation regarding their toxicity levels. Since it is one of our favorite fruits, we needed to investigate further! Think you can guess how many you would have to eat in order to have any pesticide residue in your system?

Dr. Robert Krieger, the Director of the Personal Chemical Exposure Program at the University of California, Riverside, was curious about how pesticide residue affects our health as well. He decided to answer a question similar to this in his paper, Perspective on Pesticide Residues in Fruits and Vegetables. Using the data from the USDA’s Pesticide Data Program (PDP) from 2000-2008, Dr. Krieger analyzed how much pesticide residue a man, woman, or child could consume safely. For purposes of creating a “worst case scenario”, Dr. Krieger calculated the numbers using the highest pesticide residue found on 14 popular produce items during the 2000-2008 time period.

This produce list included apples, blueberries, carrots, celery, cherries, kale, lettuce, nectarines, peaches, pears, potatoes, spinach, strawberries, and red bell peppers. The methodology for the PDP analysis included a normal rinse under running water of the produce before testing (typical of consumer habits). Dr. Krieger’s analysis showed that, through a healthy (and even slightly excessive diet) no man, woman, or child could consume enough pesticide residues to reach a level where it negatively affected their health.

Using strawberries as an example, the Pesticide Residue Calculator from SafeFruitsandVeggies.com illustrates that a woman could consume 2,042 servings of strawberries in one day without any negative effect from pesticides! This result holds true even if the strawberries have the highest pesticide residue recorded for strawberries by the USDA.

To monitor the safety of pesticides used on crops and other foods, the USDA, (through the PDP), routinely measures pesticide residues to determine the safety for human consumption. Of the 20 years that the PDP has been testing residues, 98-99% of the crops and commodities have tested below, and most often significantly below, tolerance levels set by the EPA.

So why do farmers use pesticides?

photodune-4084763-beetle-insect-cartoon-illustration-xsWhile we understand the concern over the use of and exposure to pesticides, it is important to think about this subject from a pest management perspective. According to the USDA’s Economic Research Service, approximately 600 species of insects, 1,800 species of plants, and numerous species of fungi and nematodes (worms) are considered serious pests in agriculture. No farmer wants to use pesticides, but crops can be rapidly defoliated if pests are not managed properly. When pests are not managed, crop yields and quality suffer significantly. Any decrease in crop yield and/or quality will hinder a farm’s overall productivity. Additionally, when pesticides are not used and crops are lost, food prices increase to make up for the drop in supply.
Remember pests don’t discriminate between organic and conventional crops. Producers, both organic and conventional, make a variety of decisions about the application of pesticides that affect their farm’s efficiency, including pesticide selection, pesticide combinations, timing, method of application, application rate, application equipment, and spray additives. Many use information about pest infestations obtained through local agricultural extensions, scouting or monitoring, and grower associations to make application decisions within their economic threshold. And while an organic farmer will do their best to manage their crops with organic methods, they are allowed to and often refer to the fertilizers, herbicides, and insecticides approved by the NOP to control pests and improve yields.
Furthermore, when most people hear the word “pesticide” they imagine something quite dangerous.  What they don’t know is that over the last several decades, the old chemicals have been steadily replaced by much less hazardous ones. An analysis of the 2010 PDP data by Steve Savage found that 36.6% of the residues detected that year were for chemicals that are less toxic to mammals than things like salt, vinegar, or the citric acid in your lemons. Of these detections, 73% were for pesticides that are less toxic than the vanilla that is in your ice cream and 90.5% were less toxic gram per gram than the ibuprofen that is found in Advil. Lastly, 95.4% of the detected residues were from chemicals that are less toxic than the caffeine that is in your coffee each morning. Unlike the impression that is sometimes conveyed by particular consumer groups, “pesticide” does not equal “danger.
So, we know that, considering normal consumption rates, pesticides are not going to negatively affect your health. But let’s also take a look at the big picture.

photodune-5918470-cup-of-coffee-xsDetected residues on fruits and vegetables are less toxic than the caffeine that is in your coffee each morning!

[Tweet “Pests don’t discriminate between organic and conventional crops! A look at pesticides.”]
The reality is that more food is needed to feed a growing world population. Given the limited farming land and a concern for the sustainability of our environment, pesticides are needed to harvest maximum produce per acre. Most simply put, farmers need to produce MORE with LESS. The research and development of better pest management practices and improvements in technology and cultivation methods is imperative in agriculture. Integrated Pest Management, for example, is a system that establishes a sustainable approach to managing pests by combining biological, cultural, physical, and chemical tools in a way that minimizes economic, health, and environmental risks. Additionally the use of bio-pesticides, which are used in both conventional and organic farming, has increased. If California is any example for the rest of the country—and it produces 80% of our fruits and vegetables—the use of bio-pesticides in that state increased in both amount and area treated (1.0 million-pound increase, 23% increase; 325,000-acres treated, 5.1% increase) from 2013-2014.

Regardless of whether you shop organic or conventional, it is important to understand how important conventional farming is to our nation’s food supply. Organics will never be able to feed the world. The cost of production is too high to make it the primary growing option for farmers. Conventional farming is more cost effective and the safety levels of pesticides are constantly regulated and ensured.

To better understand how farmers work to provide healthy, viable crops, we spoke to a third generation strawberry farmer in California who manages roughly 40 acres of land, with an approximate 50/50 split between organically and conventionally grown strawberries. (You also might be interested to know he buys conventional!)

A skilled farmer and organic veteran at this point, he told us he has been growing organic since the early 1990s. And although his organics do command a higher market price, the financial and physical effort that goes into producing an organic strawberry is at least twice that of conventionally grown strawberries.
The issue with using approved organic fertilizer is the overall success rate. He explained that organic fertilizer inputs could never bring the soil nitrogen levels to where they should be for growing strawberries. That also means that more applications of fertilizer were needed throughout the growing process—not to mention organic sprays are 8-10x more expensive than conventional.

Bug Vacuum

Additionally, we learned that there are few effective herbicides in organics, and that weeds are primarily managed manually or by tractor. In terms of insecticides, a farmer relies on beneficial organisms, pyrethrin based insecticides and even a bug vacuum! (which he also uses on his conventional crops). And still, the yields of his organic crop are always less than his conventional crop. That’s a lot of manual work that goes into growing those strawberries! His ability to manage his conventionally grown strawberries with minimum amounts of tested and regulated pesticides provides yields that are over 2-3x that of his organic crop.
Our farmer friend was generous with his time in speaking with us, as now is harvest season for strawberries. He is concerned about people’s impression of farming and left us with this:

Farmers are really good stewards of the land.  We take care of our land because that is what we live by. We abide by laws and regulations and provide a product that is safe for the consumer.  We would love for people to understand that the food that comes out of the United States is the safest food around.

Meet a strawberry grower

The Bottom Line:

If you are buying conventional you don’t have to fear the use of pesticides. U.S. agricultural scientists, researchers, and farmers continually work to create, manage, and produce the safest food supply in the world. Pesticides help farmers make the most of their land. To ensure food safety in your kitchen, be sure to wash your fruits and vegetables before eating. Any trace pesticide residues that remain will not negatively affect your health.


“Pesticide Data Program.” Agricultural Marketing Service. Web. May 2016. <https://www.ams.usda.gov/datasets/pdp>.

“Agricultural Marketing Service.” Agricultural Marketing Service. Web. Apr. 2016. <https://www.ams.usda.gov/>.

Klonsky, Karen. Comparison of Production Costs and Resource Use for Organic and Conventional Production Systems. Department of Agricultural and Resource Economics, University of California. PDF.   http://aic.ucdavis.edu/publications/NRCSKlonskypaper.pdf

“Applied Mythology.” : Do You Really Need to Buy Organic Foods To Avoid Pesticide Residues? Web. May 2016. <http://appliedmythology.blogspot.com/2012/09/to-you-really-need-to-buy-organic-foods.html>.

“Agricultural IPM.” Agricultural IPM. Web. May 2016. <http://npic.orst.edu/pest/agipm.html>.

“CAES: Fact Sheets.” CAES: Fact Sheets. The CT Agricultural Experiment Station. Web. May 2016. <http://www.ct.gov/caes/cwp/view.asp?a=2815>.   Removal of Trace Pesticide Residues from Produce

“Food and Pesticides.” EPA. Environmental Protection Agency. Web. May 2016. <https://www.epa.gov/safepestcontrol/food-and-pesticides>.

“Farmers Fighting Pest Pressures in Crops.” Extension Daily. 2015. Web. May 2016.

“Cornell University.” IPM on Farms. Web. May 2016. <http://nysipm.cornell.edu/about/defining-ipm/ipm-farms>.

“Insect Pests of Vegetables.” Insect Pests of Vegetables. Web. May 2016. <http://ipm.ncsu.edu/vegetables/pests_vegetables.html>.

“Minimizing Pesticide Residues in Food.” Minimizing Pesticide Residues in Food. Web. May 2016. <http://npic.orst.edu/health/foodprac.html>.

“United States Department of Agriculture.” NASS. Web. May 2016. <https://www.nass.usda.gov/Surveys/Guide_to_NASS_Surveys/Chemical_Use/#description>.

Pest Management Practices. ERS-USDA. PDF.   http://www.ers.usda.gov/media/873656/pestmgt.pdf

Pesticides and Food: How We Test for Safety. CA Dept. of Pesticide Regulation. PDF.   http://www.cdpr.ca.gov/docs/dept/factshts/residu2.pdf

“Reducing Pest Pressure.” Reducing Pest Pressure. Web. May 2016. <http://www.sare.org/Learning-Center/Bulletins/A-Whole-Farm-Approach-to-Managing-Pests/Text-Version/Reducing-Pest-Pressure>.

“Six Reasons Organic Is NOT The Most Environmentally Friendly Way To Farm.” Science 2.0. Web. May 2016. <http://www.science20.com/agricultural_realism/six_reasons_organic_not_most_environmentally_friendly_way_farm-110209>.

“Summary of Pesticide Use Report Data – 2014.” Summary of Pesticide Use Report Data 2014. Web. May 2016. <http://www.cdpr.ca.gov/docs/pur/pur14rep/14sum.htm#trends>.