By: Chris O'Shea
The orange, as we know it — juicy and nice to look at — is dying. A disease called citrus greening is rapidly spreading across the world, and taking healthy oranges with it. Once a tree becomes infected with the disease, the fruit rots and becomes green. The only way to stop it is a method that isn't sitting well with people, leaving farmers and others who depend on oranges with a complex situation.
Citrus greening — also known as "Huanglongbing" and citrus vein phloem degeneration (CVPD) — has been around since 1943. It originated in China, and has spread since. The first reported cases of CVPD in America were documented in the early 2000s. The impact of CVPD is quick and extreme.
"Although the disease syndrome differs to some extent according to citrus variety, common symptoms are yellowing of the veins and adjacent tissues, followed by yellowing or mottling of the entire leaf, occasionally with corking of the veins," explains the Food and Fertilizer Technology Center. "This is followed by premature defoliation, dieback of twigs, decay of feeder rootlets and lateral roots, decline in vigor, and ultimately, the death of the entire plant. Diseased leaves become hardened and curl outward, while young leaves developed after premature defoliation are small and slender, with symptoms of zinc deficiency. Trees affected with greening become stunted, bear multiple off-season flowers, most of which fall off, and produce small irregularly shaped fruit with a thick, pale peel. The fruit from these trees is bitter."
This is why the growers in Florida — the state produces the second-most oranges in the world, behind Brazil — are looking into altering orange's DNA to save them. While genetically modified organisms (GMOs) strikes fear into the average Whole Foods shopper, the growers appear to have little choice. As of now, there is no cure for CVPD. As one University of Florida professor recently told the New York Times, "People are either going to drink transgenic orange juice or they’re going to drink apple juice."
Unfortunately for citrus growers, the public really might opt for the apple. "If various polls were to be believed, a third to half of Americans would refuse to eat any transgenic crop," reports the Times. "One study’s respondents would accept only certain types: two-thirds said they would eat a fruit modified with another plant gene, but few would accept one with DNA from an animal. Fewer still would knowingly eat produce that contained a gene from a virus."
The only breakthrough so far has been splicing the tree's DNA with some genes from a spinach leaf. Those have been shown to deter the spread of CVPD. But that's far in the future. For now, because of regulations and consumer pushback, the GMO oranges have to be tested and re-tested before they even hit the ground. In other words, CVPD is winning, because the efforts to fight it are bogged down in complex issues.
[Pic via Flickr - Miggs Lives]