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.

“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
Apples & Pears
March 27, 2017
It’s a Family Reunion at IFTA
Some of my fondest memories on the road are at IFTA conferences. Read More
Apples & Pears
March 27, 2017
Out of this World Expectations for ‘Cosmic Crisp’ Apple
With millions of trees going into PNW orchards, Washington State growers are betting big on ‘Cosmic Crisp. The shift in varieties planted and more took center stage when the International Fruit Tree’s Annual Conference met in Wenatchee, WA. Read More
Miss Florida Citrus and Imperial Polk County 2017 winners Paige Todd and Rachel Smith
Citrus
March 27, 2017
Say Hello to the New Miss Florida Citrus
Storied tradition continues with crowning of the industry’s newest advocate. Read More
Irrigation
March 26, 2017
Tips to Maximize Water Efficiency in Your Almond Grove
Editor’s note: Spencer Cooper joined the Almond Board of California last fall as Senior Manager, Irrigation and Water Efficiency. Western Read More
SWD On Raspberry
Berries
March 26, 2017
Outsmarting SWD with Social Media
Entomologist in Kentucky uses social media for pest updates, trap catches. Read More
honeybees
Citrus
March 25, 2017
New Videos Offer Tips on Planting Pollinator Habitats
A new video series on planting flowering habitats is designed to help growers support crop pollinators. Read More
Freeze protected blueberry bushes in Florida
Berries
March 25, 2017
Florida Blueberry Crop Escapes Slap from Late-Season Cold Snap
Freeze protection tactics prove fruitful as local producers look to gain from Georgia’s loss. Read More
Apples & Pears
March 25, 2017
Two MAIA Releases Available for Growers, Hobbyists
‘Crunch-A-Bunch’ is an early ‘GoldRush’ and ‘Bakers Delight’ is a secret ingredient for baking. Read More
Nuts
March 24, 2017
Foreboding Fungus Vexes Almond Growers
In parts of California, almond growers have recently become concerned about Ganoderma root and butt rot. To put this concern Read More
Citrus
March 24, 2017
Marrone Bio Introduces Biostimulant to Reduce Sun Stress
Haven Anti-transpirant helps to reduce transpiration of fruit, nut, and vegetable crops. Read More
Campus of Massey University in New Zealand
Citrus
March 23, 2017
Count Down the World’s Top 30 Agriculture Colleges
Familiar names and several new faces among annual ranking’s elite. Read More
Pest Control
March 22, 2017
Fear of GMOs is Impacting Quality Food Research [Opinion]
Perhaps the greatest threat to our industry is a public that values instinctual opinion over careful research and the findings of experts who have dedicated years to their field of study. Read More
Business Planning
March 22, 2017
How HortTech Is Solving Grower Challenges
Dozens of tech companies are looking for solutions to real-world problems vegetable growers face. We take a look at what it could really mean for you and your business. Read More
Production
March 22, 2017
Weighing the Good and Bad of Six Soilless Media Options
Trying to decide which growing media is the right one for your greenhouse vegetable production? Take a look at these six options. Read More
Citrus
March 21, 2017
Industry Groups, Ag Leaders React to Proposed USDA, EPA Budget Cuts
New plan would slash USDA spending by 21%. Read More
The Latest
Apples & Pears
March 27, 2017
It’s a Family Reunion at IFTA
Some of my fondest memories on the road are at IFTA conferences. Read More
Apples & Pears
March 27, 2017
Out of this World Expectations for ̵…
With millions of trees going into PNW orchards, Washington State growers are betting big on ‘Cosmic Crisp. The shift in varieties planted and more took center stage when the International Fruit Tree’s Annual Conference met in Wenatchee, WA. Read More
Citrus
March 27, 2017
Say Hello to the New Miss Florida Citrus
Storied tradition continues with crowning of the industry’s newest advocate. Read More
Irrigation
March 26, 2017
Tips to Maximize Water Efficiency in You…
Editor’s note: Spencer Cooper joined the Almond Board of California last fall as Senior Manager, Irrigation and Water Efficiency. Western Read More
Berries
March 26, 2017
Outsmarting SWD with Social Media
Entomologist in Kentucky uses social media for pest updates, trap catches. Read More
Citrus
March 25, 2017
New Videos Offer Tips on Planting Pollin…
A new video series on planting flowering habitats is designed to help growers support crop pollinators. Read More
Berries
March 25, 2017
Florida Blueberry Crop Escapes Slap from…
Freeze protection tactics prove fruitful as local producers look to gain from Georgia’s loss. Read More
Apples & Pears
March 25, 2017
Two MAIA Releases Available for Growers,…
‘Crunch-A-Bunch’ is an early ‘GoldRush’ and ‘Bakers Delight’ is a secret ingredient for baking. Read More
Nuts
March 24, 2017
Foreboding Fungus Vexes Almond Growers
In parts of California, almond growers have recently become concerned about Ganoderma root and butt rot. To put this concern Read More
Citrus
March 24, 2017
Marrone Bio Introduces Biostimulant to R…
Haven Anti-transpirant helps to reduce transpiration of fruit, nut, and vegetable crops. Read More
Citrus
March 23, 2017
Count Down the World’s Top 30 Agricultur…
Familiar names and several new faces among annual ranking’s elite. Read More
Pest Control
March 22, 2017
Fear of GMOs is Impacting Quality Food R…
Perhaps the greatest threat to our industry is a public that values instinctual opinion over careful research and the findings of experts who have dedicated years to their field of study. Read More
Business Planning
March 22, 2017
How HortTech Is Solving Grower Challenge…
Dozens of tech companies are looking for solutions to real-world problems vegetable growers face. We take a look at what it could really mean for you and your business. Read More
Production
March 22, 2017
Weighing the Good and Bad of Six Soilles…
Trying to decide which growing media is the right one for your greenhouse vegetable production? Take a look at these six options. Read More
Citrus
March 21, 2017
Industry Groups, Ag Leaders React to Pro…
New plan would slash USDA spending by 21%. Read More
Cold Protection
March 21, 2017
Freezing Temperatures Hit South Carolina…
Peaches, blueberries, and strawberries among crops damaged. Read More
Citrus
March 21, 2017
Since When Did Eating Get So Complicated…
The bottom line to all this is the way we eat is undergoing massive disruption. Read More
Apples & Pears
March 21, 2017
Two More Lost Apple Varieties Found In S…
Amateur apple detective strikes again with two more finds in abandoned orchards near state park. Read More