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Five Tasty Reasons To Reconsider GMO Crops

Originally posted at Applied Mythology. Below is an excerpt:

Why Are There Such Major Threats to Our Favorite Crops?

Pests are nothing new, and they have often disrupted agriculture in the past. However there are two unique aspects of our times that exacerbate such risks:

  1. With ever-increasing global travel and commerce, new exotic pathogens, weeds, and insect pests are spread around the world at a faster rate than ever before. These create severe problems which threaten entire crops

  2. As climate changes, pests are often able to thrive in new places or at different times of year than in the past, creating much more difficult control issues.

This enhanced potential for existential pest threats is particularly problematic for many of our favorite luxury food and beverage crops. What we really appreciate about those crops has to do with complex quality factors. They are also perennial crops. You can't just breed a new pest resistant variety of these crops because it is so hard to maintain the quality, and because each generation of seed takes years to produce. Conventional genetic solutions would take decades at best, and the new pest challenges don't give us that luxury. Here are some of the key threats to things we enjoy:

California Wine Grapes

Glassy Winged SharpshooterThe bacteria-like pathogen Xylella fastidiosa is native to the US and lethal to the premium wine grapes that were brought here by Europeans (Vitis vinifera). However, it wasn't an unmanageable issue in California because the insect vector, the Bluegreen Sharpshooter, mainly stayed in riparian areas and only occasionally spread the pathogen into vineyards. 

Then, in 1989, a new vector, the Glassy Winged Sharpshooter, arrived in California. It thrives on citrus and frequently visits grapes. For now that vector has been restricted to Southern California and is being managed there with insecticides and quarantines on moving plants that might spread it. But if and when the sharpshooters invade the key North Coast wine districts, things could get ugly for wine lovers. There is also the risk that the vector and Xylella could get transported to places like South America, or Australia. Xylella recently made it to Europe. There are native American grapes that are resistant to this pest, but they don't make premium wine. There may be a genetic engineering solution, but for a perennial crop one would ideally want multiple approaches to manage resistance. Even if we had a solution today it would take a long time to replant or re-graft our vineyards. We should really be having a very public discussion about this solution now, but we are not.

Specialty Coffee From The Americas

Coffee infected with rustThe Coffee Rust pathogen wiped out production in Java and other areas that had supplied England in the 1800s. They had to switch to tea. Later, the coffee industry escaped the disease by moving to places like the highlands of Central and South America. The rust pathogen caught up around 1985, but only recently has the climate changed such that the disease has become a major problem in those regions.

Traditional breeding for resistance is possible by crossing the desirable Arabica types with the hardier Robusta types, but that requires chromosome doubling of Robusta - a step which can cause all sorts of genetic damage. Then to back-cross to restore the full quality of the Arabica would take a very long time, probably not something that can preserve the livelihoods of the small-holder coffee farming families that have been the backbone of the industry in the Americas. Realistically, we in the rich world will probably be able to get our morning dose from some other geography, but because genetic engineering has been "off the table" for coffee since the mid 1990s, lots of poor families are being hurt and coffee prices are rising.

Florida Orange Juice

The Florida juice industry has largely moved to the not-from-concentrate, premium orange juice segment because of competition for frozen juice coming from Brazil. Now, the whole Florida industry is in serious decline because of a new bacterial disease spread by a new, exotic insect vector. There is an excellent description of this situation in the New York Times by Amy Harmon. Growers have funded some research that may have found a "GMO" solution, but whether they will get to use it is up to brand-sensitive juice marketing companies. Far better funded research would have been appropriate in a rational world. When I was growing up there was a ubiquitous add for orange juice that said, "a day without orange juice is like a day without sunshine." I don't know if that is really true, but at least when it comes to the not-from-concentrate kind, we might get to find out.


BananasThe 1930s hit song, "Yes, We Have No Bananas" was actually about "Panama Disease" (Fusarium oxysporum) which wiped out the previous banana of commerce (the Gros Michel variety). Fortuitously, a new banana called the Cavendish was found in Vietnam. It was resistant to the disease and also suitable for shipping (most bananas are not). Now there is a new strain of the same pathogen called Fusarium Tropical Race 4, which is destroying the Cavendish in Asia and recently in Australia and Mozambique. It is probably only a matter of time before someone inadvertently transports this soil-borne pathogen to the Americas. There has been a little work on a solution, but nothing close to what would be needed to protect the future supply of this popular fruit or the jobs of a great many people involved in growing and shipping it. Maybe its time for someone to do a cover of "Yes, we have no bananas."


Cacao, the crop from which we get chocolate, has many pests, but two in particular have been spreading throughout Central and South America leading to dramatic declines in production. The diseases are called Witch's Broom and Frosty Pod, and according to leading researchers, Frosty Pod alone "presents a substantial threat to cacao cultivation worldwide." Major confectionary companies have funded genome sequencing, but on their websites they imply or state outright that they won't be pursing genetic engineering solutions (Nestle, Mars, Hershey's). Once again, the people at the most risk here are small-scale farmers, particularly those in Africa, should these pathogens make it there from the Americas.

Why GMO?

Modern genetic engineering approaches could be very logical ways to protect these particular crops. The genetics that drive quality are complex, so we have good reason to stick with the best varieties we know. Genetic engineering is a way to bring in some useful gene without disrupting the genetic base for quality. Sometimes that might involve moving a gene from a wilder or less desirable member of the same or a closely related species into the high quality background. Sometimes it might mean moving a gene from some other plant when no same-species options are available. It could mean simultaneously pursuing the use of several different genes so that they could be co-deployed for resistance management purposes. It might mean engineering a rootstock that would protect the traditional variety grafted on top.

Also, with these crops it would be feasible to maintain separate "GMO" and "Non-GMO" product options. "Identity preservation" is the norm for crops like this because they have the value and quality attributes to justify the cost of keeping records, using different equipment etc. There may be consumers who will never trust the science, and in a rich society they can continue to buy a non-GMO option. What does not make sense in a rich, technically sophisticated society is that a vocal minority has already compromised the future supply for all of us. You can't get back more than a decade of potential progress just by throwing money at a problem in a crisis. What makes even less sense is that the people who would lose the most in these pest-driven scenarios are, in many cases, the poorer people whose labor we require in order to enjoy these luxuries.

Read the full post here.