To follow by Email (RSS Feed)

Monday, June 3, 2019

...And We've Got To Get Ourselves Back To The Garden

Kids at the original Woodstock event  (Photo by Ric Manning, Wikimedia Commons)

(This post originally appeared on the podcast site, POPagriculture, 5/23/19)

Did you know that 2019 marks the 50th anniversary of Woodstock? There may be a 50th anniversary celebration this August in Watkins Glenn, NY, but it seems to have run into some organizational issues.

The original Woodstock music festival was a defining moment for those of us in the “Baby Boomer” generation. It highlighted the emerging “counter-culture” thinking of the time about “sex, drugs, and rock and roll.” There were also anti-war and environmental themes. I was only in junior high at the time, so I just heard about Woodstock on the news and I remember seeing the rather shocking pictures featured in Time Magazine. We all got to hear some of the featured music on the radio from festival headliners including Jimi Hendrix, Janis Joplin, the Grateful Dead, and Joe Cocker. Crosby Stills and Nash performed the emblematic song titled “Woodstock,” and that major hit was then featured on their 1970 LP “Déjà vu.”

The song, “Woodstock”, was actually written by the Canadian artist, Joni Mitchell. Joni has always been one of my favorites because she combines creative music with profound poetry. Her lyrics certainly spoke to our generation’s concerns and to our search for identity. If you haven’t heard the song in a while or if you’ve never heard it you should really give it a listen. You can hear both Joni’s version and the Crosby Stills and Nash version on YouTube.

The song spoke of meeting a “child of God” who was “walkin’ along the road” “goin’ down to Yasgur’s farm” to “join in a rock ‘n’ roll band”  and to “camp out on the land” to get his “soul free.” It talked about going there “to lose the smog.” And about “feeling like a cog in something turning.” The war allusion was, “I dreamed I saw the bombers, riding shotgun in the sky, turning into butterflies above our nation.” Joni even made what sounds like a climate change reference with the line, “we are stardust, billion-year-old carbon.”

So, you may be wondering, “how is Steve going to connect this bit of pop culture with agriculture?” That comes from the chorus of the Woodstock song that ended with the line: “… and we’ve got to get ourselves back to the garden.” 

That desire to get “back to nature” was maybe one of the better instincts from that era and still resonates today. There are many ways to pursue the goal of getting in touch with nature, but I think that Joni was “right on” with the whole garden thing. We may not have gotten to rock out with the hippies at “Yasgur’s Farm,” but there are lots of benefits if we do “get ourselves back to the garden,” and that’s what I’ll explore on today’s podcast!

Now gardening is a pursuit that goes back a long time before Woodstock. After all, that was supposed to be Adam and Eve’s job in the “Garden of Eden” in the ancient Genesis narrative! For millennia, people grew a lot of their own food, and not just those who were full time farmers.

My grandpa retired in 1962 and became an even more serious gardener.

My grandpa retired in 1962 and became an even more serious gardener.

I had a happy introduction to the joys of gardening, courtesy of my beloved grandfather. He was a WWI vet who took seriously the WWII era challenge to grow a “Victory Garden” to support the war effort. From early childhood, I got to help Grandpa with his garden, and I’m sure those memories are part of why I have always gardened in the various places I and my family have lived over the years.

Its not like many people in the “rich world” today need to garden to eat. We have the privilege of a remarkable, diverse, tasty and affordable food supply.  I’ve observed the steady improvement of the store-available food since the days of Woodstock, particularly when it comes to the fresh produce options, whole grains and other healthy choices.

But there are still a lot of great reasons to garden. Today it is popular to talk about “urban farming.” I’d argue that is essentially still “gardening.” I’d rather reserve the title of “farmer” for someone for whom growing things represents a significant part of their income, but whether it’s called urban farming or gardening, it’s a good thing.
A good day's harvest from my garden a couple of years ago

Even when I had 25 grapevines in the back yard, I still considered it gardening.
Even when I had 25 grapevines in the back yard I still considered it gardening

I believe there are lots of good reasons to grow things, whether that involves a sizable part of a suburban yard or just some pots on the apartment or condo balcony. So, here is a “click bait” kind of title for today’s segment: “Seven Great Reasons to Get Ourselves Back to the Garden.”

1. Gardening can be a nice break from our indoor lives.
I’m sure that a lot of my listeners are like me in that our day-to-day work involves a lot of time sitting at a desk and looking at a screen. It’s great to have a change of pace, get outside to enjoy the sun, get our hands dirty, and maybe do a little physical work. I’m lucky enough to work from home so I can use time in the garden as a sanity break.

2. There is satisfaction in “doing it yourself.”
It’s fun to be able to say, “I grew this!” Your garden production doesn’t have to make a significant contribution to your food supply to get that pleasure. For instance, we may never grow our own wheat for bread or many other staple foods, but that does not diminish the fun for what we can produce.

A good day's harvest from my garden a couple of years ago.
A good days harvest from my garden a couple of years ago

3. Gardening is an excellent opportunity to teach kids about where food comes from.
As our society becomes ever more urbanized, we have generations of kids who have no experience other than seeing food bought from stores or restaurants. That’s not a good thing for many reasons, but it is really fun to see the wonder that a child can experience when they can actually watch something grow and then enjoy eating it. Again, this upside does not require homegrown produce to be any significant part of their diet, just that they see how food is grown and/or maybe get their hands a little dirty helping you in the garden. My kids enjoyed helping and now I sometimes get to provide that perspective with my grand kids who are growing up in very urban London. For the text version of this segment, there is one of my all-time favorite pictures that shows the expression on the face of my then 4-year-old granddaughter when she picked her first apple.

My granddaughter picking an apple in my garden.
My grand daughter picking an apple in my yard

My little backyard tree was no great specimen, which I can partially excuse by the fact that apples are not well-adapted to Southern California. Still, it was worth growing it if only to give her that one particular childhood experience.

4. Gardening allows us to have something special to share with others.

One experience that gardening teaches us is that when growing things, you sometimes end up with way more than you can handle or consume. You might be able to deal with that by canning, drying or freezing. I remember that Grandpa always seemed to have lots to share with us and he was such a serious gardener that he provided a lot for his neighbors. If you’ve ever grown zucchini squash, you may have had those times when the crop grows way faster than you even want or need to work into your meals. 

--> -->
My grandpa out in his garden.
My Grandpa out in his garden

Grandpa used to joke that during peak zucchini season he would put a bag of the squash at a neighbor’s door, ring the doorbell and slip away so they couldn’t turn it down! I never had to do that, but I definitely had times when I wasn’t keeping up on the squash harvest and some became three foot long “pool toys” for my kids. We used to have a fig tree in the yard and when those became ripe, we had far more than we could eat. We had friends and family members, however, who love figs and who were thrilled to get that treat.

Some of our figs.

5. A garden can be a way to get certain treats that aren’t generally available to buy. 

Now as I said earlier, food choices that are available in modern, U.S. grocery stores are remarkable. There is a whole POPagriculture podcast about that topic titled, “An Apple a Day.” But even so, there are many really interesting and tasty crops that are either too delicate to make it to a store or not known well enough to represent a market. A garden can provide some real treats of that nature.

Beet greens from the garden.

For instance, I like to grow beets specifically for the leafy tops. That particular option isn’t all that available in great condition in the store.

Recently I found a local nursery that specializes in tropical plants and I bought a lychee tree and a dragon fruit tree. I’m spoiled enough to live in a frost-free location where those specimens might just survive in my care and provide some options, that at least for now, rarely show up in stores. I also like to grow some lettuce plants and then harvest it by the leaf, just enough for the salad that night so that it is super fresh.

Freshly picked lettuce leaves.

Now, “bagged salad” is definitely a nice option in stores today, but it’s just fun to supplement my salad until it gets too warm here and my lettuce goes to seed and becomes very bitter. Wherever you live, you might check with the local “Master Gardener” groups to see what backyard specialties you might be able to grow.
I like to grow tomatillos to make green sauce.
Tomatillos for making your own green sauce

6. A garden can give you options to do something “green” with unavoidable food waste.
If you consume a lot of fresh produce, there are the parts that have to be trimmed off, husked, or peeled. If your local waste treatment plant does anaerobic digestion, the “greenest” thing you can do is send it down the disposal. What you really don’t want to do is send something like this plant waste into the landfill. As a gardener, you can have a “worm box” or maybe a small compost pile to recycle these materials. If nothing else, you can just bury it in the garden to let it decay and return to the soil. For instance, I like to fertilize things in my garden with my coffee grounds.
You can get the top of a store-bought pineapple to root and grow another pineapple in your own yard.
Did you know that you can grow a new pineapple by planting the top you cut off of one from the store?
7. Gardening can help us to better appreciate what farmers do for the rest of us.
I’ve left what I consider to be the best reason to garden until last. In the modern, developed world, only a tiny subset of our population is directly involved in food production. While that is great because it allows most of us to pursue other fulfilling vocations, it separates us as consumers from the realities faced by those who do produce food. Even worse, we can drift into a sort of “armchair quarterback” stance in our thinking about how we think farmers should do their job. It doesn’t help that farmers are often the subject of seriously unfair and misleading narratives in the press, in the agendas of some activist groups, or on social media. As a non-farmer who got to spend my career with some connection to farmers, I got into blogging because I was so troubled by the misinformation out there about who farmers are, what they do and what they care about. I would encourage people to participate in some farm tours or agro-tourism to get themselves a somewhat more balanced view. If you can’t go to a farm yourself, gardening is a remedy for this sort of possible blind spot and can give you a bit more perspective on the many challenges and benefits to growing food.
Lots of things can go wrong in the life of a food crop and if you garden you are likely to experience at least some of those challenges – just without the potentially catastrophic economic effects faced by farmers. There can be damaging weather events like hail, frost, heat waves or drought and those will show a gardener just how delicate a plant might be vs the ravages of nature.
The other harsh reality of nature that a gardener is likely to experience has to do with pests. You might have the only local specimen of some kind of plant in your garden or on your balcony, but it is amazing how specific insects and diseases can find your crop and mess it up.

My grand daughter's reaction to seeing pest damage on one of my apples! She thinks that “pests are yucky!”
My grand daughter's reaction to finding a pest on the apple!
If you go to your local garden supply store, you can get some products to help you safely manage these pests. There are certainly not as many advanced options as are available to farmers or others with the appropriate certifications based on extensive training, but there are options that will work for you. You might want to check to see if there is any local guidance available to you through a Master Gardeners group or your state Cooperative Extension agents.

Hornworms always seem to find your tomato plants.

One thing I really wish I could buy for my garden would be “GMO” sweet corn. There is usually nice sweet corn available in stores, but it would be fun to grow and it is a crop that can be grown just about anywhere at least some time during the year. Also, my grandpa used to grow sweet corn back in the days when you really had to cook it almost immediately after picking to keep it from going starchy. Breeding advances have turned that into a store-ready crop, but I’d like to grow it for nostalgic purposes, thinking back to the days when Grandpa would say, “Get the water boiling and then I’ll pick some corn.”

A nasty surprise when husking sweet corn.
A nasty surprise you can find when you husk your sweet corn!
There are some nasty “worms” that eat their way into the ears of corn from the tassel end, and its really gross to start husking the corn where instead of finding nice kernels, there is a wriggling caterpillar in its frass (read “bug poop”). Farmers, including organic farmers, have been spraying a biocontrol bacterium called Bt since well before Woodstock, but for that to work you have to re-apply  it every few days. Sweet corn hybrids exist that have been engineered to make their own Bt protein, so they might never need to be sprayed. That elegant and environmentally friendly option has been almost completely denied to farmers and certainly to gardeners because of anti-GMO phobia and the related brand protectionism in food retail. I really wish that wasn’t the case – more for the farmers than for me and other gardeners.

My Frank-N-Food plush asking "Why?" I let this happen to my corn.
My Frank-N-Food plush asking why I let this happen to my corn?
Sometimes, however, I do see some great pest management options available to consumer gardeners. For instance, I’ve purchased tomato plants at the local nursery, which were grafted on to pest resistant “rootstocks.” Often the “heirloom” tomato varieties that we gardeners like to grow are really wimpy when it comes to dealing with soil-borne diseases and nematodes, but if they are on a robust, resistant rootstock they will do much better.
Now, a gardener is likely to accept a much higher level of “cosmetic” pest damage on their own produce than they would in the store, but seeing what pests can do to plants is a good education and hopefully something that generates some perspective about what farmers have to deal with as they manage pest challenges on a much larger scale. A gardener might sometimes get by without any real pest issue, particularly on a quickly growing crop. The same is true when farmers get lucky in a given season. Still, a gardener is likely to get a dose of reality about the fact that nature includes many organisms that like to compete with us for the crops and food that we need someone to produce.
So, whether you want to go to the 50th anniversary version of Woodstock this summer or not, there are still lots of good reasons to want to “get ourselves back to the garden.”

Wednesday, May 1, 2019

Florida Citrus Industry Is Facing An Existential Threat From Bacteria, But A Virus Offers Hope

Orange Juice (Image by AlbanyColley, Pixabay)

(This article was originally posted on Forbes on 4/30/19) When I was growing up in the early 1970s there was a ubiquitous television ad promoting Florida orange juice including the line, "a day without orange juice is like a day without sunshine." That "dark day" could be approaching soon, at least in terms of the juices we get from the "Sunshine State" and the livelihood of the farmers who grow the trees that have long supplied us.

The iconic orange juice industry in Florida is facing an existential threat because of a severe bacterial disease of citrus that was introduced to the US from Asia in 2005 (the Asian Citrus Psyllid insect that helps to spread it was first found in Floria in 1998). A Florida homeowner may have inadvertently introduced the bacterium to the US in citrus budwood he brought home from Asia to graft onto his backyard trees.  The malady is often called "Citrus Greening," but in Asia it is known as Hualongbong and so we now tend to call it HLB. HLB has since spread to virtually all the back yard and commercial citrus trees in Florida, killing many of the trees and forcing the growers to struggle to keep the remaining ones alive with intensive nutrient feeding and other stop-gap measures.  

Oranges showing symptoms of "Greening" or HLB (USDA image)

In 2013 journalist Amy Harmon wrote an excellent article for the New York Times about the history of this crisis titled: "The Race To Save The Orange By Altering Its DNA."  She described in detail how this long-anticipated threat finally materialized and how the Florida growers funded university research to explore possible solutions including genetic engineering.  A biotech solution was identified using some defensive peptides that are naturally made by spinach plants, but as Harmon explained, that sort of "GMO" solution was a hard sell to the big, brand-sensitive juice companies who buy the oranges.  I have been personally disappointed to watch the way that the juice companies have acquiesced to the pressure to use a "non-GMO" label.  That unfortunate marketing ploy now appears on all the brands including the one company that relies exclusively on Florida fruit as opposed to a mix with imports. This is a classic case of how "control of the food supply" is really the in the hands of anti-technology activist groups, not the big companies most often so accused.

This is my current bottle of FL grapefruit juice, but I have to "hold my nose" when buying in because of the misleading "non-GMO" label (Ruby Red grapefruit was generated using mutagenesis breeding, no a problem but definitely "genetically modified")

But realistically, deploying a biotech trait like this in a perennial crop would be quite slow because the growers would have to start over with new trees or possibly graft onto the existing rootstocks and regrow the entire above ground part of the plant.  In the mean time, the industry has been steadily declining and the fear is that it will reach a point where it just isn't worth maintaining the juice plants.  Orange juice can certainly be imported, but for a time the Florida industry was able to distinguish itself by its better tasting "not-from-concentrate" advantage.  

This same destructive disease now threatens the citrus industries in other states.  The disease and its insect vector are already present in California, but for now it has been contained to mostly urban/suburban areas in the southern part of the state.  If it spread to something like the tangerine/mandarin groves of the Central Valley and other parts of the $3.4 Billion California citrus industry, that would be a disaster (think Cuties(r), Halos(r), lemons, navel oranges, grapefruit etc.)
From my current bag of mandarins (again sadly with the misleading non-GMO label)

But I'm happy to say that today I'm writing about a newer technological approach to deal with this disease.  An extended public comment period ran through Tuesday May 30th in which the USDA asked for feedback on the question of whether or not to approve the commercial deployment of a different way to protect orange trees from the HLB disease.  It is something which could possibly be implemented much more quickly than by genetically engineering the trees themselves.  This is something that could be presented in a way that would make it sound scary, but its really not. 

There is a virus that infects orange trees called Tristezea.  It also came from outside the US and began causing problems in all the citrus growing regions of the US in the 1960s.  At first it was also a lethal disease, but eventually it was found that by avoiding certain rootstock types, the virus could infect the trees with no symptoms at all.  (Virtually all fruit crops have been grown on rootstocks for a centuries).  In Florida today all but the youngest trees are infected with Tristeza, but with strains that are benign for trees when they are on the rootstocks now used.  The new biotech solution is to add genetic sequences for the spinach antimicrobial peptides to the RNA of the virus, and then get that virus to infect orange trees.  This could be done with new trees when they are in nurseries, but it may be possible to also "graft transmit" the virus into at least they younger trees already out in the commercial groves.  In this case that new small branch does not need to take over, it just allow the virus+peptides to move into the other parts of the existing trees.  In any case, modifying the virus is far more efficient than having to separately engineer and propagate each of the popular citrus varieties in the industry.

A small scale trial that was run for several years confirms that this sort of virus inoculation can make the trees resistant to the HLB pest and to allow full productivity.  As part of that experiment, trees with no virus were planted all around these test blocks and then followed to see if the engineered virus ever moved into them (the virus can be transmitted by aphids under certain circumstances).  In fact the virus didn't move, though even if it did it wouldn't be a big issue.  Also, over time the modified virus loses the genes for the spinach peptides which is then another barrier to any sort of unwanted spread.  Also it is clear that the Tristezea virus does not have any bad effects on other crops or wild plants since the virus has been very widespread for decades without causing problems in other species.

I've included the comments that I submitted to the USDA below concluding with my hope that the experience in Florida will pave the way for using a similar approach in California if we ever have to save that industry as well. I sincerely hope that the USDA does approve this new method and I sincerely hope that those who control the juice plants will both help the growers that supply them and trust consumers to be smart enough to listen to the logic about this technology.

This is the Website about the USDA comment process:

This is the link for comments followed by what I submitted:


I am writing in support of this release permit as I believe that it is a very logical strategy with the potential to literally save the citrus industry in Florida. If it proves successful it could play a similar role in the unfortunately likely scenario that HLB becomes a more serious threat to citrus production in other regions such as California. I am a plant pathologist with a Ph.D. from the University of California, Davis. My own work there was with fungal diseases, but I spent a lot of time in the lab of Dr. Robert Shepherd, a National Academy virologist. Starting at that time in the late 1970s I had many close colleagues who were working on the early stages of plant genetic engineering and I have continued to follow that field ever since. The progress of the field has been remarkable. 

In preparation for this comment I read all the available documents from the USDA site and corresponded with some of the university researchers who have done the relevant work on issues like the potential for recombination and transmission of the modified Tristeza virus.

This approach of using an asymptomatic strain of the virus is particularly logical for this perennial crop. To engineer the orange scion itself would require the generation of separate "events" in each of the important cultivars and then a delay to graft those onto existing trees and bringing that new "top" into bearing. Using the virus makes it far more feasible to utilize more than one combination of antimicrobial peptides which will help to prevent the development of resistance in the HLB bacterial pathogen population. 

There are several convincing reasons that this strategy is likely to be safe with regard to any potential for spread to non-target citrus or to other plant species. There is very low rate of aphid transmission even under ideal lab conditions. The track record of zero transmission to sentinel plants in the previous limited release further demonstrates that the modified virus is extremely unlikely to move beyond the intended trees. The fact that recombination will likely lead to loss of the peptide part of the viral genome is another safety factor and will again allow for the deployment of different peptides in a follow-up grafting step if that is needed down the line. The fact that the Tristeza strains to be used are already ubiquitous in Florida citrus represents a multi-decade "experiment" showing that this virus represents no threat to other species or to citrus that is grown on the rootstocks for which infections by these strains are asymptomatic. With the tremendous advances in the speed, sensitivity and affordability of genetic assays, it will be possible to rigorously monitor the efficacy and safety of the strategy. As for the anti-microbial peptides from spinach - long experience supports their safety from a food point of view.

I believe that this release can be the culmination of an exemplary example of an effort funded by the grower community and partnering with the public, academic community to employ state-of-the-art science.

Saturday, March 23, 2019

Do You Really Need to Worry About Pesticides on Your Kale?

Bundle of Kale (Wikimedia commons)

Last week the Environmental Working Group (EWG) published its annual “Dirty Dozen List” and highlighted Kale near the top of it’s list of foods with “pesticide residue contamination.” They want you to buy your Kale as Organic.  EWG claims to base that recommendation on data from the USDA’s Pesticide Data Program (PDP), but a closer look at the actual data suggests a far different conclusion – that the Kale in our food supply is quite safe and that there is not the big difference between organic and conventional that they imply.

Since EWG gets much of its funding from large organic marketers, it is not surprising that their recommendation is to buy organic, but the 2017 PDP testing included 67 samples that were labeled as USDA organic (13% of the total for Kale).  Many of those organic samples had detectable residues representing 31 different chemicals, only one of which is approved for use on organic crops (Spinosad).

Now the levels at which chemicals were detected on the organic were very low and of no health concern based on the very conservative “tolerances” set by the EPA through its extensive risk assessment process.  However, the same can be said for the 455 conventional Kale samples tested the same year of.  The residues we are talking about here are hundreds to thousands of times below the relevant tolerance (see graph below).

In theory there wouldn’t be any synthetic residues on organic, but the USDA’s certification rule allows for “inadvertent” presence of synthetics at 5% or less of the EPA tolerance. (There is a separate USDA-Organic compliance testing program that looks for residues, and in that case the 5% rule applies).  98.9% of the 2017 PDP detections for organic Kale samples would meet that standard, but so do 98.1% of the residues on conventional samples.  Not so different, eh? In the graph above, only the red part of each bar would be a technical violation of the organic rules and none of the Kale detections for either conventional or organic exceeded the tolerance. Note that neither category is actually “dirty” based on a rational, scientific assessment.

Now, there were about three times as many residues/sample found on the conventional Kale, but the USDA does not even test for a great many of the pesticides that are approved for and regularly used on organic.  This would include “natural products” such as mineral-based materials (e.g. sulfur or copper compounds), petroleum oils, plant extracts, and biologicals).  Those sorts of products make up a substantial part of what gets applied to Kale. Thus, pesticides which are not part of the PDP testing make up 65% of the total pounds of crop protection agents applied to kale and 44% of the treatment acres (see graph below from the most recent available year of California use data).  Approval for organic is entirely based on what is considered to be “natural” and the USDA is quite clear that the classification is not about relative safety.

The acreage of Organic Kale has been increasing over the last 15 years and with it the use of the organic-allowed pesticides.  (See the example of sulfur use on Kale as linked to organic acreage in the graph below).

If the USDA tested for residues the natural product pesticides, the number of “detections” for organic samples would certainly increase. But as with the synthetics, the results would most likely indicate that this is a perfectly safe vegetable to consume whether or not it is organic.  Bottom line, the wisest thing for consumers to do is to ignore the fear-mongering of the EWG and simply enjoy a healthy diet including lots of this and other fruits and vegetables.

Sunday, May 20, 2018

A Revised Assessment of 2016 USDA Pesticide Residue Detection Data

On March 25 and May 10th I posted articles about the USDA’s annual Pesticide Data Program (PDP) that takes a look at chemical residues on various commodities in the US food supply (mainly fruits and vegetables).  I described the program and its various levels of published summaries as a valuable example of a transparent data resource, which it certainly is.  Unfortunately I made an error in my analysis, using the wrong year’s “sample table” (10,365 rows) to identify which of the residue detections in the “results table” were from organic or conventional sources (31,981 rows drawn from a 2.2 million row table).  This meant that I erroneously overstated the number of pesticide detections on organic samples.  I had reported an average of 2.6 detections/organic sample and the actual number is 0.75 detections per sample vs 3.2 detections/sample for conventional.  Journalist Tamar Haspel brought this issue to my attention.  She was skeptical about the similarity of detection frequencies I had described for organic and made the effort to check the original data.  I very much appreciate her persistence on this question.  I want to apologize for that error and any wrong conclusions that came from that.  I do this analysis of the data each year as a personal project unrelated to my consulting and ag communications jobs, so the responsibility for this error rests entirely on me.  I am striving to remove the content that was based on the error, let people know about the mistake, and with this post, get the analysis right. (Revised Forbes posts here and here)

Fortunately there is no change in the most fundamental conclusion that should be drawn from the USDA’s data: our food supply and particularly the fruits and vegetable are very safe and so we can all enjoy them and benefit from their health-promoting characteristics.  This is fully true for both organic and conventional options.  What also remains true is that analytical chemists are capable of finding tiny trace levels of chemicals, but finding those does not mean something is dangerous.

So, what has changed based on getting the data right is that the data shows a distinctly lower number of synthetic pesticide detections on organic samples (~1/4 as many).  That fact has to be balanced with the reality that there are many natural pesticides commonly used on organic farms, which are not detectable with of the testing technologies used in this particular USDA program.  For the most part these materials have very low mammalian toxicity, but that is also true for a great many of the synthetic pesticides that are part of the testing.  Conventional farmers also use these same pest control options, but possibly not as extensively as would be needed in organic production.  Again, if there was testing for these particular pesticides, it would almost certainly do nothing to change the paradigm of overall safety of the food supply.

Although there were more residues detected per sample for conventional vs organic (3.2 vs 0.75 detections/sample), there are similarities in the distribution of those residues in terms of level relative to conservative, EPA tolerances

One retained conclusion that is of interest is that 80% of the residues detected on conventional crops are at levels low enough so that they would not be considered as a violation of the organic rules because they are 20 times lower than the EPA tolerance.  In the case of organic (for which this statistic is 84%) the assumption is that the presence of such low level residues is “inadvertent.”  For conventional it means that by following the EPA label requirements, growers can even exceed the safety factors for which those requirements were designed through a rigorous risk assessment process by EPA. 

The data does show that even though there are fewer residues detected on organic, 16% of those are of synthetic chemicals at levels that exceed what is acceptable under the organic rules (the corresponding number for conventional is 20%).  This certainly does not represent any kind of health risk, but it isn’t consistent with the organic “brand” or with the convenient fiction that organic means “no pesticides.”

Finally, the Environmental Working Group’s “Dirty Dozen List” remains a misleading and science-free publication.  It is corrosive for trust in the food supply and if believed, has the potential to make consumers pay more than they need to, or even worse, be less likely to consume the quantity of fruits and vegetables that health experts would recommend.

Once again, I apologize for my earlier error with the data.