Help On The Horizon

Help On The Horizon

Not one of Florida’s 600,000 acres of citrus is safe from the threat of greening. Some southern Florida groves have reached a 60% infection rate, and projections are for the disease to continue to spread. Removing infected trees and spraying for psyllids have not proven to be effective control measures.

But there is some good news to report. Researchers at the U.S. Horticultural Research Laboratory in Ft. Pierce are getting closer to finding new ways to slay the yellow dragon. Laboratory Director Calvin Arnold discusses some of the most promising research for short- and long-term greening remedies.

Investigating Guava

Several studies are underway to better understand how guava interplanted with citrus (a production practice used in Vietnam) suppresses psyllids. Lab tests have shown psyllids cannot live on guava. The next step, which is already in progress, is field testing. Plant pathologist Tim Gottwald and his team are cooperating with several Florida citrus growers to perform field trials in which guava trees are first planted, followed a year later by citrus trees.

“We know a volatile comes off leaves of guava to repel psyllids,” says Arnold. “This is our primary focus. But we also have preliminary data that the essence of the guava fruit also provides some repelling effect.”

The problem with using the guava fruit to repel psyllids, however, is that the Caribbean fruit fly is attracted to the fruit, creating a whole new pest problem. So that’s why USDA researchers are focusing on the leaves of the guava. By irradiating guava trees, the scientists can produce plants without seeds or fruit.

Intensifying Funding

Florida’s citrus industry saw $7.5 million in disease research funding for the 2007-2008 season. As part of its 2008-2009 Research Funding Strategic Plan, Florida Citrus Mutual (FCM) is seeking to secure more than $34.7 million to fund greening and canker research. This includes state and federal legislative appropriations as well as USDA monies.

The Florida Citrus Commission approved a preliminary budget that includes $20 million in grower box tax dollars for disease research, the full amount FCM recommended.

“We prefer growers do not have to plant guava (taking up valuable citrus acreage),” says Arnold. “The best option would be for a private company to develop a product to disperse the volatile in the grove. One possibility could be an atomizer attached to the trunks of trees at certain intervals that emits the volatile to move up the trees.” He thinks it would be easy to get EPA approval for this, since the volatile is a naturally occurring substance.

Bts Offer Possibilities

Another psyllid control method the lab is looking into is the use of Bacillus thuringiensis (Bt), a bacterium that acts as an insecticide. Bt has been proven to kill psyllids. The Bt research is the result of a group of citrus growers who visited Monsanto’s leadership in St. Louis to ask for help in the fight against greening.

“Monsanto has one of the best collections of Bt isolates in the U.S.,” says Arnold. “We stand a reasonable chance of economic control if we find the effective Bt.”

Trap-Crop Technique

Greening research also is being conducted on orange jasmine. Psyllids prefer orange jasmine over citrus. The idea is to use jasmine as a trap crop. Growers would plant rows of jasmine in the vicinity of their groves, then spray only the jasmine to kill the insects.

“These three techniques (guava volatiles, Bt, and orange jasmine trap crops) could be very immediate solutions,” says Arnold. “The answer to greening likely will not be a single method, but a combination of several new production techniques and methods.”

Enduring Remedy

“The long-term solution is to modify existing commercial varieties through genetic engineering so the trees are resistant to greening and canker,” says Arnold. His team is transferring anti-microbial peptides to give resistance, have already transformed Hamlin and Carrizo, and presently are evaluating these plants to determine if there is resistance to greening.

Arnold says growers may ask, “If we have the technology to engineer disease resistance in trees, why haven’t we done so already?” First, it takes time. It can take three to five years to grow the modified tree in the greenhouse and then the field. Second, there has been a fear of genetically modified organisms (GMOs) in the market, especially in Europe. In past discussions with growers, Arnold says they’ve told him GMOs would kill their export market. But now, the fear is gradually subsiding as growers become more desperate for greening solutions. Now they are saying, “Modify the trees, and we’ll deal with the market issues.”

According to Arnold, it’s important to understand that with genetic engineering, a Valencia would still be Valencia. It would look the same, taste the same, and grow the same. The only difference would be the disease resistance — and that could make all the difference in the world for the survival of Florida’s citrus industry.

Leave a Reply

Featured Stories

CitrusIt’s Time For Young Farming Leaders To Engage [Opinion]
October 21, 2014
Florida Grower editor Frank Giles says there are capable and talented youths in the ag field ready to step up and take the reins. Read More
Farm ManagementResearchers Finding Biofuel Fits For Florida
October 21, 2014
Alternative crops identified that are suited for the state's climate and can easily be processed for power. Read More
CitrusBayer CropScience Launches New Award To Recognize Produce Industry Innovators
October 21, 2014
Award recognizes innovation that enhances the role of produce in creating better lives. Read More
FruitsCalifornia Department Of Food And Agriculture Awards $3.6 Million To Assist Farmers With Drought
October 21, 2014
State Water Efficiency And Enhancement Program highlights projects implement irrigation systems that reduce water and energy use. Read More
FruitsWashington State University Researchers See How Plants Optimize Repair Of Sun Damage
October 21, 2014
Results could lead to development of crops that recover from sun damage more easily. Read More
CitrusReport: Major Food And Agriculture Employers Can’t Fill Vital Jobs
October 21, 2014
Current shortage of young farming professionals means ample employment opportunity for the next generation. Read More
More Vegetables6 Savory Tomato And Pepper Varieties For Florida Growers
October 20, 2014
Leading vegetable seed companies highlight a half dozen high-performance selections for producers in the Sunshine State. Read More
CitrusGrowers Need To Take The Ball And Run — Now! [Opinion]
October 18, 2014
Help yourself, your farm, and fellow colleagues by becoming more involved in your industry. Read More
CitrusLegendary Florida Citrus Grower And Advocate Passes
October 17, 2014
Joe L. Davis Sr. will be remembered for his straight talk and sage advice. Read More

The Latest

CitrusIt’s Time For Young Farming Leaders To Engage [Op…
October 21, 2014
Florida Grower editor Frank Giles says there are capable and talented youths in the ag field ready to step up and take the reins. Read More
Farm ManagementResearchers Finding Biofuel Fits For Florida
October 21, 2014
Alternative crops identified that are suited for the state's climate and can easily be processed for power. Read More
CitrusBayer CropScience Launches New Award To Recognize Produ…
October 21, 2014
Award recognizes innovation that enhances the role of produce in creating better lives. Read More
FruitsCalifornia Department Of Food And Agriculture Awards $3…
October 21, 2014
State Water Efficiency And Enhancement Program highlights projects implement irrigation systems that reduce water and energy use. Read More
FruitsWashington State University Researchers See How Plants …
October 21, 2014
Results could lead to development of crops that recover from sun damage more easily. Read More
CitrusReport: Major Food And Agriculture Employers Can’t Fi…
October 21, 2014
Current shortage of young farming professionals means ample employment opportunity for the next generation. Read More
Apples & PearsInvasive Pest Found First Time In U.S. At Border Crossi…
October 20, 2014
Moth known to feed on apples, apple buds, leaves, and shoots, is found in a container full of pump valves originating in China. Read More
More Vegetables6 Savory Tomato And Pepper Varieties For Florida Grower…
October 20, 2014
Leading vegetable seed companies highlight a half dozen high-performance selections for producers in the Sunshine State. Read More
CitrusGrowers Need To Take The Ball And Run — Now! [Opi…
October 18, 2014
Help yourself, your farm, and fellow colleagues by becoming more involved in your industry. Read More
CitrusLegendary Florida Citrus Grower And Advocate Passes
October 17, 2014
Joe L. Davis Sr. will be remembered for his straight talk and sage advice. Read More
GrapesNew American Viticultural Area In Northern California E…
October 17, 2014
“Eagle Peak Mendocino County” lies entirely within the North Coast viticultural area. Read More
GrapesMapping Grape Crown Gall Tumor Disease
October 17, 2014
Scientists are close to cracking the disease’s genetic code, a major boon to vineyard protection. Read More
NutsAlmond Growers To Promote Bee Health
October 16, 2014
Almond Board of California announces comprehensive Best Management Practices. Read More
Cucurbits6 Juicy Watermelon Selections For The Sunshine State
October 16, 2014
Leading vegetable seed companies highlight a half dozen high-performance varieties for Florida producers. Read More
CitrusDiversification Is King For Small Farm’s Success
October 16, 2014
Being flexible and adapting to the times critical for Central Florida's Vo-LaSalle Farms. Read More
CitrusAsian Citrus Psyllid Moves Into Northern California
October 15, 2014
First detections made of damaging insect in Santa Clara and San Joaquin counties. Read More
Farm ManagementVidalia Onion Committee Reaches Younger Audience with D…
October 15, 2014
“V is for Vidalia” campaign focused on social and digital media outreach. Read More
VegetablesSakata Seed America To Debut “Tasty 10 By Sakata Coll…
October 15, 2014
The collection includes a new variety and will be launched at the PMA Fresh Summit Oct 17-19. Read More