Posts Tagged: citrus greening
Genetic modification may be only way to save citrus industry
Genetic modification is the best long-term hope for the citrus industry when faced with huanglongbing disease, according to a Reuters special report, however, opposition to so-called "Frankenfood" is expected.
Reuters centered its story in Florida, where huanglongbing, or citrus greening disease, was first identified in 2005. The devastating citrus disease is spread by Asian citrus psyllid (ACP), which made it's way into the Sunshine State in 1998.
Asian citrus psyllid was found in California in 2008; to date huanglongbing has not been found. The psyllid attacks leaves and stems of citrus, injecting a toxin when it feeds that causes leaves to twist and die. But the real threat is huanglongbing (HLB), "yellow dragon disease."
HLB can kill a citrus tree within 3 to 5 years, and there is no known cure. Once a tree is infected with HLB, the only way to prevent its spread is to remove and destroy the infected tree.
In the short-term growers are increasingly relying on pesticides to keep ACP at bay, the article said. The practice carries the risk of insects developing pesticide resistance, groundwater contamination and disruption of an integrated pest management program that depends on beneficial insects.
The biotech industry and geneticists in particular are making an all-out push to develop an effective weapon against greening, such as citrus trees genetically modified to be resistant to HLB. USDA scientist Calvin Arnold told the reporters he believes the general public is likely to accept GMO orange juice.
"I think especially here in the U.S., they're understanding transgenics a lot better. Just like people go to Taco Bell, they know they're eating crops that have been produced transgenically," Arnold was quoted.
For more on Asian citrus psyllid in California, see the UC Kearney Agricultural Center Citrus Entomology website.
North American distribution of ACP is in orange; areas with ACP and HLB are in green.
Disease watch
The Asian citrus psyllid's border crossing into San Diego County earlier this month is prompting an emotional reaction from growers. Called the "mother of all killer bugs" by Fresh Plaza, the psyllid is most feared for its ability to spread citrus greening disease.
Farmers' comments in a story that appeared in North (San Diego) County Times reflect their dismay.
- "Honestly, I don't even want to know I have the pest. Because once I know I have the pest, it's all over. I might as well throw in the towel. Honestly, I don't see any way of stopping it. What are you going to do? Tent 80 acres?" - Bob Polito, a Valley Center grower and owner of Polito Family Farms.
- "The only remedy for a plant is to take a chain saw to it so it doesn't become a point of infection for the rest of the crops." - San Diego County's agriculture commissioner, Bob Atkins.
- "It's getting to a point where it just pushes out the domestic farmer." - Ben Drake, owner of Drake Enterprises iin Temecula.
Meanwhile, a UC Riverside graduate student has discovered and named a new bacterial pathogen that could be responsible for a devastating condition in tomatoes called "psyllid yellows," according to a story in Capital Press. The bacterium could be linked to the pathogen that causes citrus greening disease.
Citrus greening threat covered by NY Times
The New York Times ran a rather technical article this week about a disease that is sending shivers down the spines of citrus growers in Florida and California - citrus greening. The disease is endemic in Florida. California growers are nervously watching the border with Mexico, where a pest that transmits citrus greening has already been found. That development was covered by the Los Angeles Times in July, as mentioned in this blog post.
This week's article, focused on Florida, included some dire predictions:
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On concerns over solving the problem by genetically modifying citrus for resistance, Jude W. Grosser of the University of Florida said, "It’ll probably come down to the point where people have to decide whether they want orange juice or not.”
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A Florida grower was quoted as saying, “Scientists have 10 years at the most to find a solution, or there’s not going to be a citrus industry in Florida.”
UC scientists are among those looking for solutions to managing the disease. The article said Abhaya Dandekar of UC Davis is working on an electronic nose to identify volatile organic compounds produced by infected trees.
UC citrus entomologist Beth Grafton-Cardwell also has her finger on the pulse of citrus greening. She is the author of an ANR publication about Asian Citrus Psyllid, which includes a lengthy section on citrus greening.
citrus psyllid