Conventional Produce Is Not Dirty, But The Marketing Tactics Of Big Organic Are

Spinach - a crop that is getting a bum rap (picture by Victor M. Vicente Selvas)

(This post originally appeared on Forbes on 3/13/17)

For each of the last twenty years, an organization called the Environmental Working Group has issued what it calls a “Dirty Dozen List.” It names crops it claims to have high pesticide residues and recommends that consumers purchase organic versions of these crops. They base their list on a seriously distorted interpretation of a taxpayer-funded testing program called the PDP (Pesticide Data Program, USDA). What the PDP actually documents is that our food supply is extremely safe. EWG has repeatedly been called out for promoting this science-free list and for the counter-productive effect it is having on produce consumption by Americans. Yet, EWG persists in employing this strategy as a means of fund raising. Presumably it also serves the interests of their corporate funders in the organic food industry (see list below).  Note that these are very large, processed food players with only one produce company in the list.

The real "dirty dozen"

In its latest campaign, EWG is singling out a few crops for added demonization – notably spinach. They highlight certain specific chemicals that were detected in spinach samples by the USDA in 2015. I have looked in detail at this same, publicly available data. It turns out that 7% of the 2015 spinach samples were organic. The very same chemicals that EWG choses to talk about were found on those organic samples. As with virtually all of the residues found on all crops, the quantities that the USDA analytical chemists found were at very low levels - well below any possible level for health concern. Still, it is ironic that the same flawed logic that EWG uses to scare consumers away from perfectly safe conventional spinach says that they should also avoid the organic alternative.

Bagged Baby Spinach (CCO Public Domain)

Experts agree that one of the best things we can do for our health is to consume a lot of fruits and vegetables (here is one example of why that makes sense). Sadly, all too few Americans do that. Spinach is one of the more popular vegetables that can help move consumers in the right direction, particularly since it has become available as a convenient fresh, pre-washed option. Discouraging consumption of any kind of spinach is a notably irresponsible thing to do, particularly through disinformation. An industry group that represents both conventional and organic produce companies (and many are both) offers an on-line calculator using the USDA’s data and legitimate toxicological information. With this tool consumers can visualize just how safe products like spinach actually are. For instance, a child could safely eat up to 310 servings of spinach a day without negative effects from the trace chemicals on that crop.

Aphids on spinach (Image by demintedmint)

As I wrote last week, organic and conventional produce are actually quite similar when it comes to the presence of low levels of pesticide residues. Because EWG singled out spinach in its recent fund raising email campaign I thought it would be worthwhile to get into the details for that crop.

For instance, EWG focuses on the synthetic pyrethroid insecticide, permethrin, which it calls a “Neurotoxic bug killer.” That sounds scary, but pyrethroids all have the same mode of action as the natural product called pyrethrin derived from Chrysanthemums (pyrethrin is used on organic crops).  As a class the pyrethroids are only slightly toxic to mammals and are considered safe enough to be in many household, garden and pet products sold to consumers.  One of the synthetic versions, Permethrin, is among the most used crop protection agents on spinach to prevent damage from caterpillar pests and infestations with aphids. These are not things we would like to find in our salads!

The USDA detected an average of 0.8 parts per million of permethrin on the 2015 conventional spinach samples. That is only 4.2% of the conservative tolerance set by the EPA, meaning it isn’t even close to something to worry about. On the organic samples from the same season, the USDA detected an average of 0.9 parts per million permethrin– essentially the same level as with conventional.

EWG also calls out the fact that traces of DDT and its metabolites were found in some spinach samples. These are unfortunate, long-term soil contaminants still slowly decomposing decades after that old product was banned. Their presence is certainly not related to whether the current spinach crop is grown conventionally or under the organic rules. Fortunately, the levels are tiny – seven parts per billion for the conventional and 11 parts per billion for the organic. These are only 1-2% of the level that the EPA considers to be of concern.

Permethrin and DDT are the products detected on spinach that the EWG chose to talk about. There were residues of 30 other synthetic pesticides on the organic spinach in 2015. The USDA does not test for at least two dozen other organic-approved pesticides that are used on spinach (biocontrol agents, mineral compounds, natural product chemicals). None of this means that organic spinach is “dirty.” Conventional spinach isn’t “dirty” either. What is “dirty” is the tactic is telling consumers they need to buy organic because of residue concerns without acknowledging that the organic products have similar, low-level residues.

In my opinion the "Dirty Dozen" should refer to the eleven big-organic companies that support the EWG and the EWG itself.

You are welcome to comment here and/or to email me at savage.sd@gmail.com

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The Many Ways Farmers Control Pests

The post originally appeared on the Putting Pesticides in Perspective (PPIP) Blog on 2/7/17 on which there are also 6 related sub-posts

Whether a farmer is growing in an organic or conventional system, his or her crop needs to be protected from damage from plant pests (insects, fungi, bacteria, viruses, nematodes, weeds…). To fail to minimize pest damage leads to inefficient use of scarce resources like prime farm land, water, or inputs. The quality and safety of the final products can also be compromised.

While materials we think of as “pesticides” play an important role, modern agricultural pest management depends on a combination of several tools and strategies which, when used together, offer a more resilient, economic, and effective means of crop protection. Though some of these practices have been part of traditional farming, many are more recent innovations. The explicit design of these multi-strategy programs began in the 1970s, and the approach is now widely adopted as integrated pest management (IPM). The optimal IPM program varies widely by crop and geography; this post will describe some examples that highlight the various components.

The approaches used to implement IPM programs generally fall into six categories:

1. Avoiding the pest
2. Employing the plant’s own genetic defenses
3. Modifying the climate
4. Disrupting the pest's life cycle
5. Fostering beneficial organisms
6. Using targeted pesticide applications

A brief introduction to each of the six approaches follows with additional links to the more detailed presentations. Each post will link back to the list above.

1. Avoiding the pest

Not all pests occur in all places either because they have not spread there or because they cannot flourish in the climate of a given region. Both of these limitations have been historically important factors to consider when deciding what crops to grow where, and these pest limitations continue to be important considerations for farmers. Long-term, this strategy is limited by climate change and by the extensive movement of people and goods around the world

   2. Employing the plant’s own genetic defenses

Plants fight back against pests by evolving a variety of defensive strategies controlled by genetic traits. Built-in genetic resistance is an attractive form of pest control for farmers, but it is a resource that requires considerable effort to employ and stewardship to maintain as an effective part of an IPM program. For some crops, farmers can maintain a seed bank of genetic variation and draw upon it to keep ahead of the pest’s inevitable tendency to evolve around plant defenses.

When genetic resistance is available, it is generally wise to complement it with other IPM elements, such as pesticides, to avoid losing the valuable traits. For many crops, conventional methods of breeding are too slow and/or complex to easily employ genetic solutions. Traditional and advanced grafting approaches offer a dual plant genetics approach that has been quite useful in many systems. Advancements in biotechnology allow farmers to use same-species resistance genes in hard-to-breed crops as well as novel genetic approaches that have shown considerable benefit in the few cases where they have been allowed to-date.

   3. Modifying the climate

In some cases, farmers can shift the microclimate in which the plant is grown enough to reduce the threat of certain pests. Various degrees of protected culture have been widely used to shield crops from rain and/or to shift the temperature regime to extend the growing season at either end. The nature of the plant canopy can sometimes be managed to reduce humidity, increase light or otherwise create a microenvironment that is suppressive to certain pests.

   4. Disrupting the pest's life cycle

Several strategies for pest control center on making it more difficult for the pests to reproduce. These range from crop rotation to insect pheromones to removal of damaged or infested plant parts. Other approaches involve the release of male insects which are sterile so that the females with which they mate do not produce any offspring.

   5. Fostering beneficial organisms 

Even pests have pests, and often there are ways that farmers can encourage these natural enemies to help keep pest populations low enough to obviate the need for other control measures. Sometimes, it is possible to actively produce and add the bio-control organisms to the system.

   6. Using targeted pesticide applications

Farmers can use a wide range of crop protection agents as part of an IPM system. In a great many cases, these agents are low hazard options in terms of environmental, beneficial, or human impact, but the use of all such agents is highly regulated on a national and state level. These crop protection agents are often important for preserving the utility of other IPM approaches, particularly genetic resistance. Farmers have many economic and practical incentives to only use these materials on an as-needed basis.

Pest control in agriculture is a multi-dimensional effort, and pesticides are just one of the important tools that farmers employ. Some of these tools have been in use for a long time and some are new. With climate change, the control of pests will become even more difficult. As the global population grows and standards of living increase, it will be even more important for farmers to avoid the sort of losses and food waste that pest cause. Fortunately, the toolbox available to fight pests is diverse and constantly improving.

You are welcome to comment here and/or to email me at savage.sd@gmail.com

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How Can Pesticides Be Safe?

Many people may find it difficult to imagine how a pesticide could ever be safe. To understand how that is possible, it is helpful to make the comparison with something more familiar: electricity.

It is hard to envision modern life without electricity. As much as we enjoy and need this source of energy, it involves some hazards. Electricity can, and sometimes does, cause injury or death.  Yet overall, we think of using electricity as a reasonably safe aspect of our lives.

Safety can’t be precisely defined. What we perceive as safe is something where the benefits more than offset the minimal risks. We can enjoy electricity’s benefits with little risk through two main strategies: 1) using low-hazard forms of electricity and 2) keeping ourselves from being exposed to hazardous forms of electricity.

The Low-Hazard Approach

Increasingly, we power the devices central to our lifestyles with forms of electricity that are practically non-hazardous. The prime examples would be our cell phones, Bluetooth devices, or portable music players that run on low-voltage, direct current electricity which is nearly incapable of causing us harm.  That same, low-hazard approach plays an important role in pesticide safety.

In the middle of the last century, a number of the early pesticides in use were chemicals that were quite toxic to mammals, and thus to humans. The U.S. began to seriously address the issue with the establishment of the U.S. Environmental Protection Agency (EPA) in 1970. Soon, the truly dangerous pesticides were removed from the market or their use was greatly restricted.

Since then, billions of dollars have been spent on the discovery, testing and regulatory review of new, far less toxic pesticide options. In the charts below, I’ve examined the toxicity of crop protection materials that have been used through looking at historical U.S. Department of Agriculture (USDA) data on Washington State apples and California pesticide reporting data from all crops in 2013. In these charts, the toxicity is based on feeding studies with rats or mice, which is used as an indicator of potential toxicity to humans. Other measures of toxicity have similar trends.

The EPA has four toxicity categories to classify the acute hazards of pesticide products. For use in apple orchards, the data show that pesticides from EPA Category I, Highly Toxic, were never more than 10% of the total pesticides used, and that their use has steadily declined. These would be pesticides as toxic as the nicotine that is sold for e-cigarettes. Only 0.2% of the pesticides applied to California crops in 2013 were in this category.

EPA Category II, Moderately Toxic, includes materials with toxicity in the same range as the capsaicin in hot peppers or the caffeine in coffee – familiar and even sought-after natural chemicals in our diets. That category represents very limited use on apples today, and only 18% of what growers applied in California apple orchards in 2013.

The pesticide use category that has grown is termed Slightly Toxic (EPA Category III). Toxicity for crop protection materials in this category is in the same range as the citric acid in a lemon or the vanillin in a vanilla bean.

The largest category of pesticides applied to apples and other crops today is Practically Non-Toxic for mammalian consumption (EPA Category IV). Comparing this to our use of electricity, we can see that low hazard is a major strategy through which we minimize pesticide risk.

To understand how something that is designed to kill or otherwise control a pest could be non-hazardous, consider the example of chocolate which has a flavor ingredient that we humans love but which can be toxic to our pet dogs. Chemicals can have different effects on different species. Scientists use the terms specificity and mode of action to describe how chemicals have their specific effects. With modern pesticides, the mode of action is normally the inhibition of some specific enzyme that is important to the viability of the pest. If the enzyme is inhibited by the pesticide, the pest might stop eating, stop growing and/or die.

That enzyme often isn’t one that even exists in humans and other animals ourselves or in other groups of organisms unlike the pest. A modern insecticide usually only affects enzymes that are found in insects or even a few kinds of insects. A modern herbicide might only inhibit an enzyme that is needed for the growth of plants. A modern fungicide inhibits an enzyme in a pathway of enzymes that is found in certain fungi. While all of these products should still be handled with a reasonable degree of caution, they are, like the electricity that powers our cell phones, low hazard and thus low risk. We can feel safe about their use.

Limiting Exposure Risk When There Is a Hazard

We still need the more hazardous forms of electricity (such as the 120 volt alternating current) for needs like lighting, heat, air conditioning etc. To minimize risk, we’ve developed safe guards such as systems of insulated wiring, childproof plugs, circuit breakers and GFCI outlets to keep us from being exposed to that hazard. Where we need 220 volt service, we have even more ways to avoid exposure. To be connected to the grid we need the extremely hazardous, high-voltage electricity coming to us from wherever it is generated. The high-power transmission lines are designed to make it unlikely that anyone will be exposed to that extremely hazardous form of electricity.

Some pesticides that we need to manage certain pests represent a possible hazard to mammals, like humans, or sometimes to other non-target organisms like birds, fish amphibians or aquatic invertebrates. The safe use of these pesticides is all about limiting exposure. For all pesticides used in agriculture, anyone who is directly involved in the mixing or application of the chemical must follow specific requirements regarding protective clothing and equipment. For low-hazard materials, that might just be gloves, closed shoes and a dust mask. For something that could be a significant human hazard, those restrictions would include a respirator and a protective whole-body TYVEC™ suit.

Restrictions can also dictate how soon after an application anyone can re-enter a treated field (re-entry interval or REI). For low-hazard pesticides, that time period can be a few hours or less. For more hazardous pesticides, the REI can be a number of days. For pesticides that are hazardous to fish or other aquatic organisms, restrictions mandate how close applicators can apply them to waterways. Similarly, for pesticides that are hazardous to bees or other pollinators, restrictions control when applicators can apply them relative to bloom times and/or times of the day when bees and other pollinators are working.

For all pesticides, the EPA conducts an extensive risk assessment and uses that information to set up a detailed set of restrictions designed to prevent the existence of any residues of concern to consumers by the time the crop is harvested. The details of this system are discussed in another post titled, Do I Need to be Concerned about Pesticide Residues on and in My Food?

The moral of this story: just like electricity, pesticides can be used in a way that meets our need for clean, productive farming while giving us a comfortable and functional level of safety.

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