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Monday, November 9, 2015

Is There Arsenic In Your Rice?

Brown Rice (image via Wikipedia)

Over the past several years there has been an active discussion about whether the arsenic that is found in various crops is of significant health concern.  Arsenic occurs naturally in many soils, and it is taken up particularly by rice.  In the US the FDA is still conducting a full-blown risk assessment; in the mean time they have issued a few cautious guidelines .  To the extent that arsenic is a concern (and I believe the jury is still out), it is not something that differs between conventional and organic.  There are some differences by the type of rice (basmati, jasmine etc), and probably by geography (but the FDA is not yet prepared to make generalizations about that).

There has also been rice/arsenic research going on in Europe and a progress report about that has just been published in Horizon - the EU Research and Innovation Magazine.  I've recently agreed to an article sharing arrangement with Horizon in which I will highlight and link to agriculture related articles that are of potential interest to the readers of Applied Mythology.  From time to time they may also do the same for articles I write that involve EU research.

The Horizon article describes four areas of research touching on the arsenic and rice question.  The first is an evaluation of arsenic levels in various samples of rice and rice-based foods in the UK.  This is in anticipation of an upcoming change in EU regulations that will set 0.1 ppm as the maximum allowable level of inorganic arsenic in foods.   Many samples were above that new threshold which is 1/2 of the prior CODEX (International standard) threshold.  The basis for the new level was a risk assessment which relied heavily on assumptions about the ratio of dangerous inorganic arsenic relative to organic forms.

Horizon also covers research in Spain, on how cultural practices, regarding water and fertilizer management, can make significant differences in the final arsenic levels.  Perhaps in time this will help farmers achieve the new, low standards.  Another research program is investigating the processes of bio-methylation and bio-volatilization which are currently poorly understood, but which may someday offer ways to minimize final arsenic levels.

The other research studies how cooking methods influence arsenic levels.  For instance cooking in excess water and draining (as is common with pasta) can remove quite a bit of arsenic.  That is of most utility for brown rice because for fortified white rice that process significantly diminishes the nutrient value of the food.

You can see more interesting detail in the Horizon post including links to the individual research efforts.

You are welcome to comment here and/or to email me at

Friday, October 30, 2015

Taking On the Merchants of Food Fear

New book available 10/29 from Amazon,, and independent book stores

(This post originally appeared on Forbes 10/29/15)
Fear has always been an effective tool for exercising influence in society, but the internet age has enabled fear-based marketing to move to a whole new level.  This is particularly true when it comes to generating fears about food as a means to sell alternatives, supplements and various magical offerings (woo).  One of the most successful and egregious examples of this phenomenon is Vani Hari, the self proclaimed “Food Babe.”  There is a new book coming out on Thursday the 29th  titled “The Fear Babe.” The book executes a thorough take-down of Hari’s claims, methods and business model.  The content is well described by the sub-title: “Shattering Vani Hari's Glass House."

Vani Hari has a degree in computer science and once worked for a large consulting firm.  She has no background in nutrition, toxicology, medicine, or agronomy, but has no qualms about pontificating on almost any issue or about giving advice for how people should protect themselves from what she paints as an sinister, unregulated and callous industry.  She created a website and enlisted her own “Food Babe Army” to supposedly protect society from the evils of the food industry.  She has been successful at times in bullying major food companies to make changes in their offerings, not based on real issues but on the angst she has been able to generate.  Of course along the way she promotes a range of diet supplements and other magical offerings to net a nice profit.  Hari is not alone in this “create fear - sell newsletters and magical stuff” sector, which also includes Dr. MercolaThe Health RangerDr. Oz and others.
 One of the biggest challenges for the authors of the “The Fear Babe” is how to address the staggering list of topics about which Ms. Hari has generated disinformation: vaccines, microwaves, yoga mat components, GMOs, food colorings, sugar, Stevia, Silly Putty, pesticides, preservatives….. to name only a few.  The book is over 400 pages long because that is what it took - not only to address the technical issues, but also to document the emotive strategies and logical fallacies that Hari so deftly employs.  The book also includes examples of the push-back that these authors and others have given as the flood of Food Babe distortions emerged (Twitter and comment threads, blog postings…).

A public domain picture of Hari

The primary authors of “Fear Babe” are active players in the realm of science communication and myth busting.  They are not in any way employees or “shills” of the system, just people who are outraged by seeing people manipulated.  You can feel that in their writing.  Marc Draco was a veteran member of Banned by Food Babe and started the site, "Food Babe in Black and White" which compiled memes about Hari prior to organizing this book effort.  Mark Alsip writes the blog Bad Science Debunked.   Kavin Senapathy is a co-founder of “March Against Myths” who blogs on multiple sites and her own loyal following known as the “Senapath Crew.” The Preface to the book is written by veteran science communicator Kevin Folta of the University of Florida.  Several other experts contribute throughout the book as well.

This book will probably never be read by those that have bought-in to the Food Babe’s conspiratorial view of the food system. But it can serve as a useful reference for those who have the opportunity to defuse some of the specific fears they see worrying their friends and families. It is well indexed and referenced, and so it can serve as a valuable resource for anyone who plays a role of rational skeptic in the internet age.

You are welcome to comment here and/or to email me at

Monday, October 12, 2015

The Productivity Of Organic Farming In The US: Mind The Gap

This warning from the London "Tube" could apply to organic farming
(This post originally appeared on Forbes 10/9/15)
The productivity of organic farming is typically lower than that of comparable “conventional” farms. This difference is sometimes debated, but a recent USDA survey of organic agriculture demonstrates that commercial organic in the U.S. has a significant yield gap.

I compared 2014 survey data from organic growers with overall agricultural yield statistics for that year on a crop by crop, state by state basis.  The picture that emerges is clear - organic yields are mostly lower. To have raised all U.S. crops as organic in 2014 would have required farming of one hundred nine million more acres of land. That is an area equivalent to all the parkland and wildland areas in the lower 48 states or 1.8 times as much as all the urban land in the nation. As of 2014 the reported acreage of organic cropland only represented 0.44% of the total, but if organic were to expand significantly, its lower land-use-efficiency would become problematic.  This is one of several reasons to question the assertion that organic farming is better for the environment.
The USDA conducted a detailed survey of organics in 2008 and then again in 2014. Information is collected about the number of farms, the acres of crops harvested, the production from those acres, and the value of what is sold.  The USDA also collects similar data every year for agriculture in general and makes it very accessible via Quick Stats.  It is interesting that they don’t publish any comparisons of these two data sets as they would be able to make comparisons on a county basis. By working with both USDA data resources I was able to find 370 good comparisons of organic and total data for the same crop in the same state and where the organic represented at least 20 acres.  That comparison set covers 80% of US crop acreage.

For 292 of those comparisons, the organic yields were lower (84% on an area basis).  There were 55 comparisons where organic yield was higher, but 89% of the higher yielding organic examples involved hay and silage crops rather than food crops. The organic yield gap is predominant for row crops, fruit crops and vegetables as can be seen in the graphs below.

The reasons for the gap vary with crop and geography.  In some cases the issue is the ability to meet periods of peak nutrient demand using only organic sources.  The issue can be competition from weeds because herbicides are generally lacking for organic.  In some cases its reflects higher yield loss to diseases and insects. Although organic farmers definitely use pesticides, the restriction to natural options can leave crops vulnerable to damage.
I’ve posted a much more detailed summary of this information on SCRIBD with the data at the state level.

There is some potential for artifacts within this data set.  If the proportion of irrigated and non-irrigated land differs between organic and conventional that would skew the data.  With lettuce and spinach it is likely that the organic is proportionally more in the “baby” category making yields appear dramatically lower.  But overall this window on farming is useful for understanding the current state of commercial organic production.  Since the supply of prime farmland is finite, and water is in short supply in places like California, resource-use-efficiency is an issue even at the current scale of organic (1.5 million cropland acres, 3.6 million including pasture and rangeland).

You are welcome to comment here and/or to email me at I'd be happy to share a data file with interested parties and to get feedback about where particular yield comparisons might be misleading.
A more detailed presentation is available at

Friday, October 9, 2015

What Is Given Up When EU Countries Opt-out Of GMO? And For Whom?

A deadline passed on Oct. 3 for countries in the EU to opt out of future "GMO Crop" planting approvals. This "opt out" arrangement was a compromise designed to also allow some other EU countries to move ahead with GM approvals - something that has been extremely difficult to do through any united EU regulatory process.  There is a possibility that farmers in these countries may finally be allowed to use 20-year-old technology that is widely adopted around the world.  On the other side of the coin, there are 19 countries have indicated that they wanted to eschew this technology indefinitely (Austria, Belgium (Wallonia), Bulgaria, Croatia, Cyprus, Denmark, France, Germany, Greece, Hungary, Italy, Latvia, Lithuania, Luxembourg, Malta, The Netherlands, Poland, Solvenia, the UK - Scotland, Northern Ireland and Wales). The scientific community in the EU is appalled by the way that politics trumps science, but their voice has had little effect.  It is worthwhile to consider what these anti-GMO countries are not giving up, what they are giving up, and who it is that will be affected by the decision.

What Isn't Being Given Up

Few if any farmers in the "opt out" countries will have to give up their prior use of biotech crops. They have never had that opportunity, so this changes nothing in terms of existing practice. Also, since this only pertains to crops grown in the EU, it won't likely change the fact that the region has been importing massive amounts of "GM" animal feed crops from countries that allow biotech traits. Countries in the EU often present themselves as net exporters of food, but that is only true in terms of net income.  Many EU countries import animal feed and then export meat, dairy and other higher value products. That part of their economy is very dependent on imports, and these current changes are in no way a move towards food supply self sufficiency in the region.
The EU consumers in these 19 countries are not giving up their own comfort.  These relatively rich countries will probably never feel any food security ramifications from this opt-out.  If their own farmers can't supply something they demand, it can always be imported, and their buying power will exceed that of other import dependent societies around the world when supplies are tight.

So overall, the vast majority of people in these 19 countries who don't farm are not giving up anything through this politically-driven decision to opt out of one particular method of plant genetic modification.  However that is not the case for everyone.

What Is Being Given Up In the 16 Opt-Out Countries- Options for Farmers

The farmers in the 19 opt-out countries do not have "GMO" crop options today, but there are potential biotech traits that would be very helpful for them in the future - a future that will be limited by this opt-out decision. (see specific examples below.) Because only a tiny minority of citizens in the developed world still farm, farmers lack political clout.

Foreground shows potatoes not treated for Late Blight, fungicide treated potatoes in the back. Image by D. Inglis

Potatoes are a major crop in many of these countries, and EU-based technology groups like the Sainsbury Lab have logically used biotechnology to move disease resistance genes from wild, Andean potatoes, into commercially relevant European potato cultivars. That is extraordinarily difficult to do through "conventional breeding" because potatoes don't normally reproduce through seed. The biotech potatoes are resistant to the disease which caused the Irish Potato Famine and which requires extensive fungicide treatment today. The potato growers in the 16 countries are being told that they must give up that option. Olives are an important, ancient, and culturally important crop in some of the opt-out countries, particularly Italy.  That venerable crop has only recently begun to face a threat from an exotic, introduced disease.  A "GMO" option might be one of the best hopes for olive farmers, but they are being told that their fellow citizens have decided to deny them that potential solution.  Many of the 19 countries have important wine industries.  They, like all wine grape growers, are growing the traditional grape cultivars that have hundreds of years of reputation.  Biotechnology is an extremely logical way to move some disease resistance genes from other wild grape species around the world.  That won't happen.  The opt-out countries are definitely giving up things that would benefit their minority farmer citizens, but when politics trumps science for regulation, the farming community will always be the loser.

The Ramifications Of These Opt-Outs Beyond Europe's Borders

If this was simply about some relatively rich countries that represent only a small fraction of global population and had negative ramifications for only their farming community, it would be one thing.  Unfortunately, throughout the history of "GMO Crops," the decisions of EU countries have had widespread ramifications in developing countries where billions of much poorer people live.  In his book, Starved for Science published in 2008, Robert Paarlberg documented how the mostly EU-based "rich world" precautionary approach to biotech crops was projected on Africa in particular, and developing nations in general. Some countries in Africa, such as Kenya are seeking to break through this blockage, but these are the exceptions. Certain environmental NGOs have made anti-GMO campaigning central to their activities in the developing world and have put tremendous effort into opposition to "GMO" options.  They have opposed insect resistant Bt-Brinjal which would be an alternative to repeated insecticide treatments, typically applied hand and even by children.

From blogger Joan Conrow who interviewed farmers in India. "“I am waiting for the Bt brinjal. We cannot continue this crop with so much spraying. After two, three days, my skin is itching and I feel nausea. Sometimes I feel like maybe I am going to die.”

They have prevented the introduction of Golden Rice which could prevent vitamin A deficiencies that often cause blindness and death in some poor regions today. They have opposed the introduction of disease resistant bananas in parts of Africa where bananas are an important part of the food supply that is threatened by a new pathogen.   This "opt-out" phenomenon in parts of the EU is likely to reinforce the role of rich world influence on policy decisions in countries where food security is a far more pressing issue.

So this round of opt-outs changes nothing in terms of current farming practice and has no real cost to the citizens in these countries who are driving the decision.  It does; however, have real costs for others.  It will deny many EU farmers potentially valuable options in the future, particularly as the science of genetic engineering advances.  It will foster continued "green imperialism" which is the export of Europe's extreme precaution to parts of the world where food scarcity is real and where farmers could greatly benefit from biotechnology.  This is frustrating considering that crop biotechnology was introduced with great care and regulatory preparation.  The technology has an excellent track record of safety as well as economic and environmental benefits.  I guess what we have learned is that there is no statute-of-limitations on saying "the sky is falling."

You are welcome to comment here and/or to email me at

Tuesday, September 22, 2015

A Closer Look At Organic Pesticides In California

I've posted an article on Forbes taking a general look at the role of organic-approved classes of pesticides in California.  The take-home points are that pesticide actives that are approved for use in organic made up 55% of the total crop use in 2013 and that those are used by both organic and conventional growers.  I also take a look at the relative toxicity (simple acute ingestion toxicity) and there is a similar range for the organic and synthetic options.  None of this is surprising because what determines whether a pesticide can be "organic" is whether it is "natural", and that is not a safety-based criterion.  The safe use of all pesticides is the responsibility of the EPA and similar regulators around the world.

In this post I'd like to delve in more detail into what these widely used organic pesticides are and why they are used by all sorts of growers.

Major Categories of Organic-Approved Pesticides

In the first graph in this post I've divided the organic-approved materials into Mineral-based, Oil-Based, Natural Products and Live Biologicals.  I'll talk about each category below.

Mineral-Based Pesticides

The mineral-based pesticides that are approved for organic include sulfur, lime-sulfur, and various forms of copper. Together these materials comprise 34% of the pounds used but only 12% of the area treated. That is because these are relatively high use-rate materials (~2 to 25 pounds/acre).

Sulfur has been used as a pesticide since ancient times. While it is essentially non-toxic by ingestion, as someone who has worked long hours in treated vineyards, I can tell you that it is quite irritating to the eyes and skin. Sulfur controls powdery mildew fungi and suppresses spider mites, but has to be reapplied every 7-10 days. It works by sublimation (direct transition from solid to gas) so it is ineffective if it is cold and can burn the crop if it is very hot. It is converted into reactive sulfur compounds in the humid boundary layer of a leaf or berry.  Conventional growers have alternatives that need only be applied at ounces/acre every 14-21 days, but continue to use some sulfur in their programs as a way to manage resistance to the newer materials (see chart below for the trend in sulfur use on premium California grapes).

Conventional grape growers today use about 1/3 as much sulfur because they have other options

The next big mineral-based material is lime sulfur.  It is used for some dormant season sprays, so its “moderately toxic” status (EPA Class II) is not an issue for crop residues.  The remaining organic mineral pesticides are the copper-based fungicides which were discovered in the late 1800s and actually saved the European grape industry when a downy mildew pathogen was introduced from the New World. Some of the copper products are Class II in terms of oral toxicity, can be persistent, and are toxic to aquatic invertebrates, but with appropriate care for where they are used, they are considered safe . Again, conventional growers have lower rate, longer interval, more effective options, but use some copper for resistance management. Coppers are also one of the few options for the control of certain bacterial diseases and for algae control in rice fields.

Petroleum Oil-based Products

An interesting organic-approved category is a collection of oils derived from petroleum (mineral oil, paraffinic oils, petroleum distillates…). These too are relatively old products used at high rates, but they are effective on mites, aphids, whiteflies, scale insects and also powdery mildews. These are also EPA Category IV – “essentially non-toxic” to mammals by ingestion.  Again, they are also used by conventional growers along with other more modern options.

JMS Stylet Oil is a major organic brand in this category

Natural Products

Spinosyn-A - some seriously fancy chemistry (image via Klever)

About 2% of the acre-treatments on California crops were with various “natural products” which are chemicals that are made by plants or from fermentations of various microbes (thus qualifying them for organic). Nature is indeed a remarkable chemist, but that is not a guarantee of safety. Some of the most toxic chemicals known are from nature. The safe use of these materials is based on the same, elaborate risk assessment that agencies like the EPA conducts for all pesticides. The most widely used natural product is the plant hormone gibberellin (540,000 acre treatments). The next biggest product (309,000 acres) is Spinosad which was introduced by Dow Agrosciences. It comes from fermentation of an actinomycete. It’s a remarkably complex chemical, but very low in mammalian toxicity (Category IV) and quite effective against all sorts of caterpillars and hard to control insects like leaf miners. Unlike the mineral or oil-based pesticides, it can move inside of the treated plant to protect newly emerging leaves.  Lately it has become available to homeowners as “Captain Jack’s Dead Bug Brew” which is a sort of silly name, but definitely something I use in my garden.

The number 6 natural product (22,500 acres treated) is a relatively recently developed, plant-based natural product that comes from a plant called Epazote or American Wormseed. The small, California company that commercialized it was purchased by Bayer Chemical Company. They have since introduced a product in Europe which is made of a mixture of the same four terpene chemicals that occur in the plant extract. That sort of product often generates much debate in the organic community about whether it is still natural, but the chemicals are the same. In any case this product is effective against various insects including thrips which are difficult to control. That is why it will be increasingly used by both organic and conventional growers.

Thrips cause these feeding scars you often see on snap peas or snow peas
The smallest category of organic-approved products are the biological control agents. The most used and famous of these are various strains of the bacterium Bacillus thuringiensis, or “Bt.” These bacteria make a protein that is selectively toxic only in the guts of certain insects (e.g some work only on caterpillars, some only on beetles and some only on mosquitoes). Together, 10 Bt-based products were applied to 320,000 acres. Some crops have been genetically engineered to express these same Bt proteins, but those would not qualify for organic. Sweet corn has been modified this way, but the sweet corn growers have been asked by their retail store customers not to use the "GMO" varieties. Instead they must make at least six more sprays a season than they would need to if they could use a Bt variety. That is a shame.

The "natural" pesticides that are approved for organic also have an important role in conventional agriculture.  They are not qualitatively less toxic than synthetics, but then virtually all the pesticides used today are only moderately toxic at most and most commonly non-toxic in the classic sense. These and the modern synthetic pesticides play an important role in the efficient use of the land, water, fuel and labor that it takes to produce food. 

You are welcome to comment here and/or to email me at

Tuesday, September 1, 2015

An Important Public/Private Partnership Is Under Attack

(This article was originally posted on Forbes 8/31/15)

A scientist named Kevin Folta at the University of Florida has been one of a broader group of public researchers who have come under hostile, Freedom Of Information Act scrutiny with the goal of demonstrating “ties to industry.”  The implication is that any connection, particularly any financial connection, between academics and for-profit businesses is inappropriate.  Not only are the tactics of this effort reprehensible, the entire premise is wrong.  I would like to explain why Folta has been doing exactly the sort of job he was hired to do and that even much more significant public/private cooperation is completely aligned with the mission of ag schools.

A map showing the locations of Land Grant Institutions
There is a network of “Land Grant” colleges and Universities throughout the US that was first set up in the late 1800s through the Morrill Acts.  Their purpose was to focus on agriculture, science, military science and engineering. They became important centers of applied research which has been of great benefit for the global food supply.  These institutions have traditionally been part of a synergistic, public/private partnership for the discovery, testing and commercialization of innovations of value to the farming community.  They also educate future farmers, the specialized scientists and engineers who become the employees of ag-related businesses, and the future faculty.

Agricultural schools also serve the function of communicating with the vast majority of Americans who have no connection to farming except their dependency on it as consumers.  This is particularly true when it comes to the applications of biotechnology to crops.  Between low overall understanding of genetics, and the active dispersal of disinformation, public distrust in “GMO crops” stands as a barrier to the commercialization of genetic engineering solutions which would be very helpful for Florida farmers.  With broader public understanding of biotechnology, sweet corn growers might be able to plant the insect resistant lines that would save them many sprays/season.  Instead grocery retailers and processors are unwilling to risk consumer reaction.  The Florida citrus industry might be able to be saved from a deadly new disease that threatens its very existence if the juice companies believed they could explain the solution to their consumers.  The Florida tomato industry could have a solution to a problematic bacterial disease based on a pepper gene moved to tomato, but that would require downstream customers in the fast food industry believing that consumers would accept it.  Thus, it makes perfect sense for a qualified public scientist in Florida to engage in a conversation with non-farmers on this topic for the benefit of the farming community he was hired to serve.  Kevin Folta not only communicates the science himself, he helps to train other scientists to do a better job of public engagement. 

The “smoking gun” in the FOIA campaign has been that Monsanto Company contributed $25,000 to the University (not to Folta) to support that science communications training program.  It is perfectly logical for them to support such a program and anyone who thinks that such a contribution would alter the science-driven content of the program does not understand the independent nature of people who pursue careers in science.

Our week in Kauai culminated in an emotionally
charged hearing of the County Council attended by
5000 people out of a population of 55,000

I once spent an entire week in Kauai with Folta where I got to witness his science communications skill and passion.  We were participating in public forums attempting the address a major, fear-mongering campaign which sought to drive the biotech seed nurseries off the island.  I saw how well Folta was able to communicate the basics of the science and how hard he worked to meet people where they were – even the most antagonistic individuals.  Folta accepted no money for himself or for the University for that effort, unlike the substantial speaking fees that were given to the various anti-GMO luminaries who were flown in by the activists with substantial funding from mainland anti-technology groups.

Unfortunately, the nasty, defamatory campaign against Folta has advanced to the point of threats against his family and laboratory.  The University has elected to transfer the $25,000 to their community food bank in hopes of defusing the controversy.  That may be a logical move, but unfortunately its demonstrates to the broader academic community that you can be subjected to nasty attacks for doing things that are fully appropriate for your job.  It shows scientists that in the Internet age, there is no real protection from this sort of modern Inquisition.  I know Folta well enough to be confident that he won’t be intimidated into silence, but I am concerned about a broader, chilling effect that could even extend beyond public outreach activities.

There are actually far more direct, but still legitimate and beneficial connections between public institution researchers and companies involved in agriculture.  Applied and even basic scientific research often leads to innovations that are patented by the university and then licensed to a company with the necessary skills and resources for commercialization.  In this arrangement the farmers get the advances, the companies get new business revenue, and the university gets royalty income that strengthens its ability to do more teaching and research.  Companies (large and small) also often bring their innovations to the appropriate university experts for evaluation.  They pay for the time and resources that the university needs to conduct the tests, and the grower community looks to those tests as an objective evaluation of new products – often in side-by-side comparisons with products from competing companies. The Land Grant colleges were designed to serve the grower base that benefits from synergistic ties between the public and private sector.  To assume that this can’t be done with integrity is both unwarranted and counter-productive.

The Freedom Of Information Act was designed to uncover wrongdoing in the public sector.  It was not designed as a means of harassing public scientists for doing exactly what they were hired to do.

You are welcome to comment here and/or to write me at

Wednesday, July 22, 2015

Olives at Risk

A very old olive orchard I visited in the hills on the Greek island of Corfu
(originally posted on Forbes, 7/21/15)

This spring my family traveled in Italy and Greece where I became enchanted with their ubiquitous olive groves.  Many are on steep hillsides and some of the trees are extremely old with beautifully gnarled trunks.  I began to think I should try to grow an olive tree at home in the San Diego area.  Then I learned some sad news about olives – news that suggests that it will become a more scarce luxury food in the future.

Although olives are an ancient crop, expanding their supply to keep up with population growth has been difficult. If we compare the production of crops in the early 1960s with that 50 years later (2005-10) almost all have increased in total tonnage, but much of that increase has come through improved yields and not just more extensive planting (see table below).  (Table)

How the supply of some vegetable oils has changed over 50 years

Olives stand out among food oils in that all the increased supply has come from additional planting.  Global average yields are 20% lower than they were 50 years earlier. No wonder olive oil is expensive.

But now, olives in those picturesque groves in Southern Europe are threatened by a deadly disease.  It is apparently a new strain of a North American organism called Xylella fastidiosa. Strains of that pathogen cause diseases of various crops, but it is not known to affect olives in California. Somehow a new, olive-infecting strain of Xylella originated in Central America and traveled to Europe via an ornamental plant.  In Italy, the pathogen is being spread by the common spittle bug and is now killing trees in dramatic fashion.
Olives trees killed by Xylella. Image from Institute of Plant Virology Italy.
Thus olives in Italy join citrus in Florida and grapes in California as examples of crops in jeopardy because of the inadvertent, global movement of bacterial pathogens or the insects that vector them.  The grape infecting strain of Xylella was only a relatively minor issue for California grapes until a new insect vector, the Glassy Winged Sharpshooter, was transported into the state – again probably on an ornamental plant.  The disease thatis killing off Florida citrus, and threatening citrus from Texas to California, arrived on an ornamental plant from Asia with both the vector and the pathogen (do we see a trend here about the movement of exotic ornamental plants?).

Problems caused by moving plant pests around the world is nothing new.  The three-century delay in the arrival of the potato late blight pathogen allowed that New World crop to become a staple, only to be decimated leading to the Irish PotatoFamine of the 1800s.  Two pests spread from North American grape species nearly destroyed the European wine industry in the late 1800s.  It is said that the movement of coffee leaf rust from Africa to Java in the 1870s was the reason that the English had to switch to tea.  However now, with ever increasing global travel and trade, many more crops are at risk. 

Although it would not be a quick solution, genetic engineering might be a good option for the olive problem as it would be for citrus, grapes, potatoes and coffee.  Whether that will ever happen is, unfortunately, another question.  Apparently the 2015 olive crop inCalifornia is looking good.  Perhaps that will take some pressure off our demand for olive oil from Italy.  In any case, we should enjoy the luxury of olives before they become even less available.

You are welcome to comment here and/or to email me at