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January 20, 2015 by Entomology Today

From  pestnet@yahoogroups.com

Are Asian Citrus Psyllids Afraid of Heights? Elevation Study May Provide Clues for Stopping Them

Asian psyllid

The Asian citrus psyllid, Diaphorina citri, was first discovered in Florida in 2005 and in Puerto Rico in 2007. Since then it has caused billions of dollars’ worth of damage by spreading a bacterium which is responsible for citrus greening disease (Huanglongbing), the most serious disease of citrus in the world. However, scientists from the U.S. Department of Agriculture’s Agricultural Research Service (USDA-ARS) in Puerto Rico and Florida have discovered that the ACP doesn’t do well at high elevations for reasons that are not yet known. Their research, which may one day lead to clues about the insect’s vulnerabilities, is published in the Journal of Economic Entomology.
After hearing anecdotal evidence that the ACP is less abundant at high elevations, Drs. Dave Hall, David Jenkins, and Ricardo Goenaga set up a two-year experiment to find out for themselves. They chose 17 different sites, ranging from 10 to 880 meters above sea level, which were monitored with yellow sticky traps on citrus trees or other plants that are preferred by the ACP.
As elevations increased, ACP populations decreased, dropping to zero when they reached 600 meters or more above sea level.
Asian psyllid nymphAn Asian citrus psyllid nymph.
“There was a strong trend in both years for decreasing psyllid abundance with increased elevation based on the number of psyllids captured on traps and the proportion of trees shown to be infested,” they wrote. “No psyllids were collected at an elevation of >600 m.”
In addition, none of the trees surveyed for citrus greening disease at high elevation sites tested positive.
What does this mean for citrus growers?
Changes in elevation result in changes in temperature, short-wave radiation, partial pressure of respiratory gasses, precipitation, oxygen content, and air pressure. If any of these can be shown to affect the development of the ACP or of citrus greening disease, then it may be possible to induce these conditions in citrus trees at lower elevations.
“Another practical implication for this study would be to put citrus nurseries >600m, where numbers of D. citri are minimal to non-existent,” according to the authors.

Open Access paper at:
– Diaphorina citri (Hemiptera: Liviidae) Abundance in Puerto Rico Declines with Elevation

J. Econ. Entomol. 1–7 (2015); DOI: 10.1093/jee/tou050
ABSTRACT Diaphorina citri Kuwayama is the primary vector of Huanglongbing, the most devastating disease of citrus. D. citri populations in Puerto Rico were monitored with yellow sticky traps on citrus trees or other psyllid host plants at different elevations, ranging from 10 to 880m above sea level. Trapping was conducted in March through May of 2013 and 2014 when psyllid populations usually are highest. Population levels of D. citri, based on the trapping data, varied among the sites, and there was a strong trend in both years for decreasing psyllid abundance with increased elevation based on the number of psyllids captured on traps and the proportion of trees shown to be infested. No psyllids were collected at an elevation of >600 m. Reduced populations at higher elevations could be a consequence of differences in temperature, air pressure, oxygen levels, ultraviolet light, or other factors alone or in combination. We discuss our results as they pertain to management of D. citri and Huanglongbing.


Dr. Ulrike Krauss
Invasive Species Consultant
P O Box GM1109
Saint Lucia
Tel. (+1 758) 713 4308
Skype: ulrike_krauss
E-Mail: saintlucia.ias@gmail.com
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Released: 31-Jul-2014 9:10 AM EDT
Source Newsroom: University of Florida Institute of Food and Agricultural Sciences

berry image

This trap with a yeast-sugar-water mixture lures and traps the spotted wing drosophila.

 

 

 

 

 

Newswise — GAINESVILLE, Fla. – Using a yeast-sugar-water mixture, berry growers can easily keep tabs on a pest that causes millions in damage each year in the U.S., a new University of Florida study shows.
Farmers can conduct a test to determine if the spotted wing drosophila is in their field – and if so, how prevalent. They punch holes near the upper rim of a covered plastic cup and pour in a yeast-sugar-water mix to about 1 inch high in the cup. The liquid mixture lures the pest, and growers add a drop of dishwashing liquid to thicken the bait and keep the bugs from escaping.

Growers check the traps once a week to see how many bugs are in them. Knowing the pest population is the first step to controlling the bug, also known as the Drosophila suzukii.

The female insect cuts a slit in the fruit’s skin and lays eggs there. The larvae consume strawberries, blueberries, blackberries, raspberries and other thin-skinned fruit, said Oscar Liburd, a UF entomology and nematology professor.

“The Drosophila suzuki is the biggest threat to berry production in the United States,” said Liburd, a faculty member at UF’s Institute of Food and Agricultural Sciences.
Scientists first saw the pest in the U.S. in California in 2008, and damage was estimated at $500 million that year. The pest caused an estimated $10 million to $12 million to Florida blueberries in 2012, Liburd said. Monitoring leads to a more profitable yield, he said.
“If you know the bugs are in your field, you can control them better with reduced-risk pest controls, which leads to more berries,” Liburd said.
Lindsy Iglesias, an entomology doctoral student, led the study as part of her master’s thesis. She worked with Liburd and postdoctoral fellow Teresia Nyoike to determine if adding a yellow visual stimulus to the plastic cups would lure and trap more bugs. Yellow attracts many insects because it resembles foliage, Liburd said.
In one experiment during 2012 and 2013, researchers compared plastic cups with and without a yellow visual stimulus and found that its absence had no effect on the number of spotted wing drosophila caught in the cups.

While doing the research, they also found that cups with yeast sugar water caught more spotted wing drosophila than those with apple cider vinegar, Liburd said. On the other hand, the yeast-sugar-water lure stinks, and is cloudy, making it tougher to see the bugs, especially after one week, he said.

Still, UF/IFAS experts encourage growers to use the yeast-sugar-water mix because it catches the bugs quickly, giving growers pest information faster, he said.
UF/IFAS scientists recommend two traps per acre. Most Florida blueberry farms are 5 to 10 acres, although some consist of 500 or more.

The spotted wing drosophila comes from southeastern Asia and is found in China, Japan, India, Korea, Myanmar, Russia, Thailand, France, Italy and Spain.
In August 2009, spotted wing drosophila was discovered in the northeast corner of Hillsborough County. As of June 2012 it had spread to several other states and 28 Florida counties. The highest numbers in Florida were recorded in Hillsborough, Citrus, Alachua and Marion counties. Florida experienced its worst infestation in 2012 and 2013 when the bug invaded every blueberry-producing county except one, Liburd said. Currently, growers are controlling the pest with chemical sprays.
The UF/IFAS study is published online by the Journal of Economic Entomology and will be in the August print edition.
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By Brad Buck, 352-294-3303, bradbuck@ufl.edu
Source: Oscar Liburd, 352-273-3918, oeliburd@ufl.edu

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http://www.newswise.com/articles/uf-ifas-researchers-find-chemicals-that-treat-citrus-greening-in-the-lab

Released: 6/4/2014 9:35 AM EDT
Source Newsroom: University of Florida
more news from this source

PLOS Pathogens
Newswise — GAINESVILLE, Fla. — A University of Florida research team is cautiously optimistic after finding a possible treatment in the lab for citrus greening, a disease devastating Florida’s $9 billion citrus industry. It is the first step in a years-long process to bring a treatment to market.
Claudio Gonzalez and Graciela Lorca led the research team that examined three biochemical treatments: phloretin, hexestrol and benzbromarone.
The team sprayed greenhouse tree shoots separately with one of the three biochemicals and were successful in stopping the bacteria’s spread, particularly with benzbromarone, which halted the bacteria in 80 percent of the infected trees’ shoots. They expect to begin field experiments with this treatment later this year. Their research was published in late April by the online open access journal PLOS Pathogens.
Gonzalez and Lorca are UF associate professors in the microbiology and cell science department, part of UF’s Institute of Food and Agricultural Sciences. The team also works under the auspices of the UF Genetics Institute.
The researchers found that benzbromarone targets a specific protein, known as LdtR, in the citrus greening bacterium. When benzbromarone binds to LdtR, it inactivates the protein, which disrupts a cell wall remodeling process critical for the greening bacterium’s survival inside a citrus tree.
“As a consequence of the chemical treatment, several genes were not expressed and the bacteria were not able to survive inside the phloem of the plant where osmotic pressure from sugar is high,” said Fernando Pagliai, a co-author of the study and a UF graduate assistant. Phloem is the living tissue that carries organic nutrients to all parts of the plant.
Benzbromarone is typically used to treat gout in humans.
Citrus greening first enters the tree via a tiny bug, the Asian citrus psyllid, which sucks on leaf sap and leaves behind bacteria. The bacteria then move through the tree via the phloem. The disease starves the tree of nutrients, damages its roots and the tree produces fruits that are green and misshapen, unsuitable for sale as fresh fruit or for juice. Most infected trees die within a few years.
The disease has already affected millions of citrus trees in North America and could wipe out the industry in the next decade if a viable treatment is not found.
UF/IFAS researchers have attempted everything from trying to eradicate the psyllid to breeding citrus rootstock that shows better greening resistance. Current methods to control the spread of citrus greening include removing and destroying infected trees.
Florida growers say they desperate for a treatment that will work.
“Every grower I know is just hanging by their fingernails, hoping and praying for a new discovery for treatment,” said Ellis Hunt Jr. of Lake Wales, whose family has been in the citrus business since 1922.
Industry experts, though, say it could be five to seven years before a new active-ingredient product could be commercially available because of the amount of time field testing takes and government regulations.
Jackie Burns, director of the UF/IFAS Citrus Research and Education Center in Lake Alfred, said because of those regulations, which are meant to ensure a safe food supply, researchers can’t accelerate testing and approval. And she noted that although the initial results of the research are promising, there is no guarantee the compounds will work under field conditions.
Other co-authors on the paper: Christopher Gardner, a research technician in microbiology and cell science; Max Teplitski, an associate professor in soil and water science; Svetlana Folimonova, an assistant professor in plant pathology; Lora Bojilova, a research technician; Anastasia Potts, a graduate assistant; and Amanda Sarnegrim and Cheila Tamayo, undergraduate students.

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U.S. Farm Bill funds $5.4 million to battle invasive species in Florida, research non-native pests
Money will help battle snails, beetles and pests

http://www.wptv.com/news/region-s-palm-beach-county/boynton-beach/us-farm-bill-funds-54-million-to-battle-invasive-species-in-florida-research-non-native-pests

Jeff Skrzypek
Apr 18, 2014

SUBURBAN BOYNTON BEACH, Fla. — – They are creep, crawly and do not belong in Florida.

Invasive species cost residents a half a billion dollars a year but now the federal government is stepping in to fork out millions to help fight the growing pest problem.

Farmers like Nancy Roe, who farms for Green Cay Produce in Suburban Boynton Beach, wage the battle on invasive species around the clock.

“Everything is so global now that shipments come in and it just takes one or two of an insect,” said Roe.

Invasive species like the Giant African Land Snail and the Ambrosia Beetle are just two bugs on the growing list of non-native species thriving in the Sunshine State.

The more critters who invade the state, the more costly it becomes for both farmers and consumers.

“Our costs are higher and that has to be passed on to somebody at some point,” said Roe.

But now the federal government is stepping in the try and combat the issue.

The government allotted $5.4 million in the 2014 Farm Bill to help fight the costly pests.

“It’s probably not enough, but I’m glad to have it. We can’t be greedy,” said Roe.

The money will fund programs to eradicate Giant African Land Snails, protect avocado plants from the Laurel Wilt and will also beef up dog inspection of incoming travelers. The money will also help research citrus greening and honeybee pests.

The Florida Department of Agriculture said in a statement the funds will, “help ensure Florida’s famed agriculture industry can continue for generations.”

Roe said the funds are a good start but much more money and research is needed just to start competing in the fight against invasive species.

“We’ll never win it. We’ll never win it completely because it’s biology and it’s a constant battle,” said Roe.

The state estimates the agriculture industry is worth $108 billion dollars.

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