This article originally ran at Forbes and has been republished here with permission of the author.
Media outlets have for the past couple of years reported regularly on the perils of bee populations and concerns that much of the planet’s agriculture will be in jeopardy without those pollinators. But unless you’re in a major citrus-producing state – Florida, California, Texas or Arizona – you probably haven’t heard that your morning orange juice is in danger of disappearing – or at least becoming vastly more expensive and coming from someplace abroad.
Oranges and orange juice, along with a range of other citrus fruits and products, face an incurable disease: a lethal, bacterial infection known as “citrus greening” or Huanglongbing (HLB), spread by a tiny Asian citrus psyllid.
The two issues — the health of bees and of orange trees — are linked in a non-obvious way. In the name of “saving the bees,” anti-pesticide activists are trying to ban the pesticides that are now the only proven line of defense against the Asian citrus psyllid.
It’s a complicated story, with lots of twists and turns. But while the activists’ claims about a pesticide-caused “bee-pocalypse” have received wide publicity and generated widespread alarm, acceding to their demands – which are based on largely spurious and highly debatable science — could steal away the only technology currently available for keeping the U.S. citrus industry alive.
New York Times science and technology reporter Amy Harmon opened her August 2013 article about the desperate struggle in Florida to save its $9 billion citrus industry in dramatic fashion: “It’s here.” The “it” – citrus greening — is caused by a bacterium, Candidatus Liberibacter asiaticus. The bacteria, spread by the tiny psyllid insects, infect the phloem and thereby block the flow of nutrients through the tree. That results in yellowed, mottled leaves and green, asymmetrical, bitter, unusable fruit; and infected trees die within about five to seven years. Meanwhile, since the trees exhibit no “greening” symptoms until the infection becomes irreversible, they serve as reservoirs for psyllids to spread the disease further.
Citrus greening is a main reason why countries in Asia, Africa, the Indian subcontinent and the Arabian Peninsula don’t have commercially viable citrus industries with exportable products. Brazil, a huge, globally important citrus producer, became infected in July 2004, but the country’s citrus industry has adapted by exploiting the country’s vast territory. When citrus greening reaches groves in one area, presaging their inevitable death, the industry simply replants elsewhere – a strategy that is less than ideal for the environment.
In August 2005, the disease was found in south Florida and has since spread to all of the state’s citrus-growing counties. It has also been found in California, where in order to preserve the state’s $2 billion a year citrus industry, a quarantine area has been created in several regions of the San Joaquin Valley’s citrus belt. The “Brazilian solution” to the scourge is not possible in the United States: We have far more limited areas suitable for citrus, all of which have long since been cultivated.
Intensive research funded by Florida’s Citrus Research and Development foundation has so far yielded only one effective treatment for maintaining a young citrus tree “greening-free” through roughly its first five years of life: a soil drench of neonicotinoid (“neonic”) pesticide at the base of the young tree’s trunk. Applied every six weeks, basal trunk application enables the chemical to be taken up through the roots and the tree’s vascular system, killing the psyllids that would infect it with C. Liberibacter when they try to feed. This route of application prevents the insecticide from affecting other flying insects or pollinators – including bees — as sprayed pesticide applications might.
Uninfected young trees are the key to saving Florida’s – and, eventually, the nation’s — citrus industry. They are the replacements for the infected trees and groves that must be destroyed and burnt. Without new “greening-free” trees, in time the U.S. citrus industry will become extinct.
Research is underway to expand the use of neonicotinoid treatment to large, mature, fruit-bearing citrus trees up to nine feet in height. Several stringent conditions must be met in order to demonstrate the safety and effectiveness of the treatment to the EPA. It must protect the tree from both psyllid attack and citrus greening infection. There must be no harmful presence of the neonicotinoid in pollen or nectar that might affect bees, or in fruit or juice that will be consumed by humans. There can be no adverse environmental effects under conditions of use. So far the results have been promising.
Unfortunately, in recent months this research has hit a bump in the road. An off-label, mistaken spray application of neonics in one of the Florida orchards of a major citrus operator, Ben Hill Griffin, generated complaints from a beekeeper that his hives suffered a direct hit with a spray – as opposed to soil-drench – application. Clearly this was an improper application of the neonics; spraying in the orchards is discouraged because it spurs the development of psyllids’ resistance to the soil drench application. Moreover, if hives accidentally receive a direct hit with pesticides of any kind, the result will be die-offs. Anti-pesticide activists were quick to generate several mostly confused and incomplete stories about the incident, insinuating that neonicotinoids exert indirect adverse impacts on the health of bees.
Inaccurate and misleading as the publicity was, it has been enough to interrupt the EPA’s consideration of the results of further neonic research in citrus – at least for a time. But it is important that momentum on this research be regained promptly. What is needed — and what researchers are investigating – is to ascertain the soil drench dosage that is sufficient to protect mature citrus trees, and a plan to rotate several different neonic pesticides, each with a different mode of action, in successive soil drench applications (to prevent psyllid resistance from developing).
Neonicotinoid soil treatment, the only near-term defense against lethal citrus greening, can buy time for plant scientists to provide a more definitive long-term solution. As New York Times reporter Amy Harmon wrote last August, several strategies that use modern genetic engineering techniques to make orange trees resistant to the citrus greening bacterium are now being explored. (Since there are no citrus varieties anywhere in the world that are naturally resistant to C. Liberibacter, conventional cross-breeding techniques are not an option.) These approaches range from incorporating into orange plants a gene from spinach or pigs to using “bacteriophages,” viruses that prey on bacteria but are completely harmless to other organisms. Some of these approaches have been used with stunning success in other crop plants to enhance resistance to other pests and diseases and to introduce other desirable characteristics.
But there are many hurdles to achieving a genetically engineered orange. One concern of citrus growers is whether the public might be resistant to the concept of genetically engineered fruit. Most people are unaware that the vast majority of corn, cotton, canola, sugarbeets and soy grown in the United States – and even Hawaiian papayas — have been genetically engineered with modern molecular techniques. In addition, since the 1930′s plant breeders have performed “wide cross” hybridizations in which large numbers of “alien” genes are moved from one species or one genus to another to create plant varieties that cannot and do not exist in nature. Common commercial varieties derived from wide crosses include tomato, potato, sweet potato, oat, rice, wheat, corn, and pumpkin.
Studies have shown that the price of foods is a strong motivator, both positive and negative, so it is likely that consumers will purchase and accept the juice from genetically engineered fruit if it is cheaper than the alternatives, especially given that the appearance and taste will be no different. (There is also the issue of whether consumers will even know that the juice is from genetically engineered citrus, inasmuch as the FDA has decided that the use of such techniques is not a “material” fact and need not be disclosed on labels.)
A second hurdle to the appearance of greening-resistant is time. Even with modern molecular techniques, the genetic engineering of trees is a slow process. Obtaining a reproducibly resistant and commercially productive genetically engineered citrus tree that yields good fruit will require many years of testing and may be a decade or more away. Likewise, the regulatory approval process is likely to drag on for years, even if there is no political obstruction of the process by the anti-genetic engineering lobby.
Thus, a long-term, genetically engineered solution to citrus greening may be years off, but the threat to farmers and consumers is with us now – and rapidly worsening. The citrus industry needs a lifeline to survive long enough to reach the long-term solution. Without the protection now offered by neonicotinoid soil treatments, the U.S. citrus industry and its associated infrastructure would likely be dead and gone by the time genetically engineered citrus trees become commercially viable.
The vital importance of neonicotinoid pesticides to the U.S. citrus industry belies the calls for a ban on these products by anti-pesticide, environmental activists, joined by some beekeepers. Their narrative contends that these advanced, systemic pesticides – the most widely used in global agriculture – are responsible for Colony Collapse Disorder (a condition in which bees mysteriously desert their hives), higher-than-normal levels of over-winter bee die-offs, and other, sub-lethal effects. But most scientific researchers recognize that today’s honey bee health problems are attributable to multiple factors, including varroa mites that vector at least 19 viruses into bee populations, other infectious diseases, poor forage and nutrition, and even the pesticides that beekeepers themselves introduce into their hives to control parasites. Meanwhile, an array of large-scale field studies and abundant real-world evidence have failed to show any adverse effects on bees from exposure to neonicotinoids at normal, field-relevant levels of exposure.
Much of New Age airy-fairy ideation about food invokes buzzwords such as “natural” and “organic.” Seductive as those concepts may be (to some), it is clear that preserving the future of a staple of the American breakfast table will require reliance on the best technologies available. There is no “natural” or “organic” solution to preserving commercial citrus production in the face of citrus greening, any more than there are effective “natural” solutions to treating cancer or multiple sclerosis.
In the long term, genetic engineering will rescue America’s citrus industry, but in the meantime, we will need neonicotinoid pesticides. To those naïfs who would ban them and condemn our citrus industry to extinction, I have a piece of advice: Go suck a lemon.
Henry I. Miller, a physician, is the Robert Wesson Fellow in Scientific Philosophy & Public Policy at Stanford University’s Hoover Institution. He was the founding director of the FDA’s Office of Biotechnology. Follow him on Twitter @henryimiller.
