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
high denisty apple orchard washington
Apples & Pears
May 29, 2016
Orchard Systems Matter With Mechanization
“It takes years to turn orchards from a big, wild 3-D tree to a narrow canopy — a lot of Read More
upclose of Israeli apple harvester
Fruits
May 28, 2016
Orchard Automation Is On The Horizon
Industry experts say the advent of fully automated orchard tasks are on the cusp of happening — with a few companies leading the automotive harvest charge. Read More
IFTA Washington Day3 6
Apples & Pears
May 27, 2016
Washington Apple Commission Elects New Leaders
The commission board also approved the export budget of $7.7 million for the upcoming 2016-17 crop, based on a crop of 135 million cartons. Read More
As this view of the San Luis Reservoir shows, California's drought is far from over. (Photo credit: David Eddy)
Fruits
May 27, 2016
California Drought Far From Over For
To preserve orchards and vineyards, growers are expected to fallow up to 350,000 acres of corn, wheat, cotton and alfalfa. Read More
These workers use a platform from Automated Ag for hand thinning. (Photo credit: Christina Herrick)
Apples & Pears
May 27, 2016
How Best To Integrate Man And Machine
If you want to implement labor-saving mechanization, you should start the conversation with the end user – your employees. Read More
Crowd protesting GMOs stock image FEATURE
Farm Marketing
May 27, 2016
Consumers Don’t Really Know What GMO Means, New Study Finds
A study from the University of Florida confirms what many farm marketers suspected: consumers don't understand genetically modified food and organisms as well as they think they do. In fact, 80% of consumers think food containing DNA should be labeled (almost as many who think GMO food should be labeled). Read More
Asian citrus psyllid closeup
Insect & Disease Update
May 27, 2016
Alabama Agriculture Department To Conduct Citrus Psyllid Survey
Currently, Alabama is the only citrus-growing state that has not yet detected citrus greening. Read More
Ready To Spring
Insect Control
May 26, 2016
Temperature, Location Key To Predicting Leaffooted Bug Pressure
This year, leaffooted bugs are expected to be a significant problem in almonds and pistachios, but watching temperature and the Read More
First-year impact of Prunus replant disease at the Firebaugh replant trial; stunted trees in the foreground row were planted in plot of non-fumigated replant soil. (Photo credit: University of California Agriculture)
Fruits
May 26, 2016
Consider Fumigating For Nematodes Before Replanting Almonds, Stone Fruit
Stone fruit and almond growers looking to replant orchards might want to invest in soil samples to assess nematode populations Read More
The Latest
Apples & Pears
May 29, 2016
Orchard Systems Matter With Mechanizatio…
“It takes years to turn orchards from a big, wild 3-D tree to a narrow canopy — a lot of Read More
Fruits
May 28, 2016
Orchard Automation Is On The Horizon
Industry experts say the advent of fully automated orchard tasks are on the cusp of happening — with a few companies leading the automotive harvest charge. Read More
Apples & Pears
May 27, 2016
Washington Apple Commission Elects New L…
The commission board also approved the export budget of $7.7 million for the upcoming 2016-17 crop, based on a crop of 135 million cartons. Read More
Fruits
May 27, 2016
California Drought Far From Over For
To preserve orchards and vineyards, growers are expected to fallow up to 350,000 acres of corn, wheat, cotton and alfalfa. Read More
Apples & Pears
May 27, 2016
How Best To Integrate Man And Machine
If you want to implement labor-saving mechanization, you should start the conversation with the end user – your employees. Read More
Farm Marketing
May 27, 2016
Consumers Don’t Really Know What G…
A study from the University of Florida confirms what many farm marketers suspected: consumers don't understand genetically modified food and organisms as well as they think they do. In fact, 80% of consumers think food containing DNA should be labeled (almost as many who think GMO food should be labeled). Read More
Insect & Disease Update
May 27, 2016
Alabama Agriculture Department To Conduc…
Currently, Alabama is the only citrus-growing state that has not yet detected citrus greening. Read More
Insect Control
May 26, 2016
Temperature, Location Key To Predicting …
This year, leaffooted bugs are expected to be a significant problem in almonds and pistachios, but watching temperature and the Read More
Fruits
May 26, 2016
Consider Fumigating For Nematodes Before…
Stone fruit and almond growers looking to replant orchards might want to invest in soil samples to assess nematode populations Read More
Farm Marketing
May 26, 2016
Who Grows Organically — And Who Doesn…
We surveyed 816 fruit and vegetable growers and found that farm marketers and vegetable growers are much more likely than their peers to embrace the practice. Read More
Farm Marketing
May 26, 2016
Farm Dinners: Your Most Powerful Marketi…
Farm dinners are a hassle. They’re expensive. And ridiculously effective. Read More
Cucurbits
May 25, 2016
Whitefly Threat Has Florida Growers On H…
Researchers, state agencies working together to prevent a potential outbreak. Read More
Crop Protection
May 25, 2016
More Apps Help Growers Identify Insects …
Berries, apples, pears, and cherries now rolled into new app series from Clemson University. Read More
Citrus
May 25, 2016
Monsanto Says Bayer Bid ‘Financially Ina…
Proposal cited as undervalued, not able to address financial, regulatory risks. Read More
Stone Fruit
May 25, 2016
Researchers Study Why Cherry Cracking Af…
German researchers studied how water uptake and fruit skin determined a cultivar’s susceptibility to cherry cracking. Read More
Farm Management
May 25, 2016
Report Highlights Benefits Of Trans-Paci…
National Potato Council says report from the International Trade Commission offers the benefits the free trade agreement would offer growers. Read More
Fruits
May 25, 2016
Farm Bureau Says EPA, Army Corps Of Engi…
AFBF told Congress that the Army Corps' novel interpretations of environmental law are threatening farmers in California and other areas of the country. Read More
Citrus
May 25, 2016
NRCS Invests $4.3 Million To Combat Clim…
The Natural Resources Conservation Service in California is committing funds to help farmers and ranchers mitigate the effects of climate change and help to reduce greenhouse gas emissions. Read More
[gravityform id="62" title="false" description="false"]