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Beloved crape myrtle in nurseries now susceptible to bacterial leaf spot, researchers say

Topic(s): Landscaping, Pests, RECs, Research, Uncategorized


GAINESVILLE, Fla. — It’s enough to send gardeners into conniptions.

Crape myrtle, a tree adored for its bright flowers that scream summer, care-free maintenance and even its colorful bark, now has a disease problem – although so far, only in the commercial nursery setting.

University of Florida researchers had been getting sporadic reports from nursery owners over the last five years of a leaf spot problem, and those reports have only increased in frequency. Through genetic testing, scientists identified the disorder as being caused by the bacterium Xanthomonas axonopodis. The disease is most likely spread by wind-driven rain or overhead irrigation, and some crape myrtle varieties are more susceptible than others.

“I’ve been working with crape myrtles for a long time, and they’ve been such a disease-resistant plant for such a long time, so it’s pretty significant when their susceptibility to disease is increased,” said Gary Knox, an environmental horticulture professor with UF’s Institute of Food and Agricultural Sciences.

The U.S. crape myrtle crop had a value of nearly $43 million in 2010, and Florida is its second-biggest producer, behind Texas. Florida has more companies producing crape myrtle, however, with 130 compared with 72 in Texas.

In the June issue of the journal Plant Disease, the UF/IFAS team outlined the first report of the disease and the work they did to identify it. They believe it is the first report of the bacterium causing leaf spot in crape myrtle.

Bacterial leaf spot doesn’t kill the ornamental tree, but creates spots on its leaves that eventually turn yellow and drop.

The researchers say, for now, the disease affects only crape myrtle commercial producers and is spread by factors such as overhead irrigation systems and large numbers of plants kept in close quarters.

The bad news is that the bacterium is widespread.

“I think you can safely say that nearly every crape myrtle producer would have the disease at this point,” Knox said.

While the disease appears contained in the commercial sector, that could change.

“Most bacterial diseases can be spread in wind-driven rain, and in Florida, we know there’s no shortage of that,” said Mathews Paret, an assistant professor of plant pathology who led the study.

Paret and Knox are based at the North Florida Research and Education Center in Quincy.

Scientists suggest an integrated management approach to the problem, rather than a silver bullet that only stops the problem temporarily.

Choosing resistant varieties, moving from overhead irrigation to drip irrigation and the limited use of bactericides would be part of such an integrated strategy, the researchers said.

The varieties Natchez, Osage, Fantasy, Basham’s Party Pink and Miami have proven highly resistant to bacterial leaf spot while Carolina Beauty, Arapaho, Tuscarora, White Chocolate, Red Rocket and Rhapsody in Pink were more susceptible in field trials funded by the Florida Nursery Growers and Landscape Association.

Steve Bender, a senior writer at Southern Living magazine, “The Grumpy Gardener” blogger and well-known gardening author, says it would be a huge disappointment if the disease ever makes the leap from nurseries to home gardens.

Crape myrtle is so close to Southern gardeners’ hearts that they endlessly debate such topics as how to spell its name (variants include crepe myrtle, crape myrtle and even crapemyrtle),  and the annual rite Bender calls  “crape murder” – an unceremonious lopping of its limbs.

It’s an iconic tree, he said, mostly because it’s little work for a big payoff.

“It’s ideally suited to the southern climate, it blooms for a long time, it comes in lots of different colors and you even get nice color in the fall,” Bender said. “It’s kind of hard to kill, and pretty much any idiot can grow one. And up until now, it’s had very few problems.”

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New videos from UF/IFAS Communications

Topic(s): Announcements, Finances, Food Safety, Landscaping, Research, Uncategorized

UF/IFAS Communications has a slew of new videos that can be used for Extension or other educational purposes. Here is a roundup:

Vacation on a Budget -  (3:31) A fun family vacation does not have to break the bank – University of Florida/IFAS Financial Expert Dr. Michael Gutter explains how to have fun in the sun without going in the red.

Scallop Harvesting 101 (3:00)  Scallop season is underway in Florida. Betty Staugler with UF/IFAS Sea Grant Extension, has some tips to help get you started.

Operation: Protect Our Pets – When Fleas Attack - (5:11) In this installment, UF/IFAS Entomologist Faith Oi addresses the different stages of the flea life cycle while UF Veterinarian Dunbar Gram demonstrates using a flea comb to look for fleas. (more …)

Biotechnology Literacy Day links are available

Topic(s): Uncategorized
Corn is one of seven crops that are genetically engineered.

See caption below

On June 18, the University of Florida’s Institute of Food and Agricultural Sciences presented Biotechnology Literacy Day, during which scientists and members of the public discussed genetic modification technology, its safety, and role in the world’s food supply. Links to the seven lectures can be found at:  http://research.ifas.ufl.edu/biotech.shtml.

Contact: Kevin Folta, 352-273-4812,  kfolta@ufl.edu

Photo caption: Corn is one of seven crops that is genetically engineered.

UF/IFAS to host public event to discuss genetically engineered foods

Topic(s): Uncategorized
Corn is one of seven crops that are genetically engineered.

See caption below

GAINESVILLE, Fla. – Genetically engineered foods are a politically charged, often misunderstood subject, and University of Florida officials hope to help shed light on the issue by hosting a public seminar June 18.

Kevin Folta, chairman of UF’s horticultural sciences department, has organized the event, scheduled from 9 a.m. until 1 p.m. in Emerson Alumni Hall. Several well-known experts will lecture and answer questions. All are welcome to attend. (more …)

Former UF/IFAS research dean has trail named in his honor

Topic(s): Uncategorized

Research Awards Ceremony held on May 15, 2014 , at the  Samuel P. Harn Museum.

John Hayes has left his role as the Institute of Food and Agricultural Sciences’ research dean, but he won’t be forgotten.

The conservation-minded Hayes was honored at the May 14 UF/IFAS research awards ceremony when local officials presented him with a sign for the “John P. Hayes Trail,” which will mark the new hiking, biking and equestrian trail will be installed at Little Orange Creek Preserve.

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UF/IFAS research: Invasive lizards could threaten Florida’s nesting reptiles

Topic(s): Uncategorized

MFDC0214_tegu leaving nest with egg

GAINESVILLE, Fla. — Research cameras trained on the nests of Florida reptiles have caught giant, invasive lizards in the act of pilfering eggs – making them a potential threat to native turtles, alligators and crocodiles.

The Argentine black and white tegu, which can grow 4 feet or more, is already found in areas populated by threatened species, including the Eastern indigo snake, Cape Sable seaside sparrow and gopher tortoise. And if the tegus’ range expands, the list of native species potentially at risk could grow to include sea turtles, shore birds and ground-nesting migratory birds.

The research team, which included scientists from the University of Florida, the U.S. Geological Survey and the Florida Fish and Wildlife Conservation Commission, outlined its findings in a paper published Monday by the journal Biological Invasions.

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Planning trumps indecision – prepare now for hurricane season, expert says

Topic(s): Disaster Preparedness, Uncategorized

GAINESVILLE, Fla. — Waiting too long to make a decision in the face of disaster is in itself a decision – and rarely a good one, a University of Florida expert in community development says.

Michael Spranger, a UF Institute of Food and Agricultural Sciences professor and Extension specialist, says deadly indecision can be trumped by one thing: Planning.

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Floridians remain conflicted on immigration; oppose eligibility for federal education grants

Topic(s): Research, Uncategorized

GAINESVILLE, Fla. — Floridians support the children of people who illegally entered the U.S. attending public colleges in their home state at lower, in-state tuition rates.

But that support fades fast when asked whether those students should be eligible for federal education grants, according to a new University of Florida Institute of Food and Agricultural Sciences’ survey of Floridians’ attitudes about immigration.

The survey of 503 Florida residents found that 43 percent of respondents agreed or strongly agreed with allowing children of those who entered the U.S. illegally to pay in-state tuition for college, but just 29 percent supported them being eligible for federal grants to help pay for college. And only 35 percent felt those students should be able to compete for public university scholarships.

The UF/IFAS Center for Public Issues Education, or PIE Center, led the study.

“It’s interesting … the results show Florida residents are interested in children of undocumented immigrants being treated fairly, but not sure they want their children to have to compete with them for grants and scholarships,” said Alexa Lamm, the PIE Center’s associate director. “I wouldn’t say the results were unexpected, but it’s telling.”

Florida legislators this spring approved a bill allowing the children of immigrants who came to the U.S. illegally to pay in-state tuition. Gov. Rick Scott is expected to sign the bill.

Much like last year’s immigration survey, Florida residents’ awareness of the E-Verify system remains low, with only 28 percent of respondents able to identify the system now being used by all agencies under the governor’s direction, including the state’s public universities. E-Verify is used to see if potential employees are authorized to work in the United States.

Georgia began requiring businesses to use E-Verify in 2011, and a University of Georgia study later estimated some $75 million in losses to agricultural producers due to shortages in harvesting help. A similar economic loss is projected for Florida should E-Verify use be required of businesses.

After being told of some of the potential challenges E-Verify could pose for the agricultural sector, 62 percent of respondents said Florida should still require agricultural producers to use the system.

The PIE Center’s survey of Floridians’ perceptions on immigration was conducted online in March, said Lamm, an assistant professor in agricultural education and communication.

As in last year’s survey, respondents assigned importance to a number of topics, and immigration came in ninth on a list of 10.  While 89 percent of respondents rated the economy as highly or extremely important, only 62 percent felt as strongly about immigration.

Jack Payne, UF senior vice president for agriculture and natural resources, said the results suggest to him that UF/IFAS may need to do more to help raise awareness about immigration issues and how they can affect the state’s agricultural sector and the economy.

“Immigration is a key issue, but it’s especially so in Florida because of its close ties to agriculture,” he said. “And if we’re going to have effective immigration policies, it’s imperative that our state’s residents are well informed on the issue.”

The PIE Center will host a free webinar on public perceptions and knowledge gaps about immigration at 2 p.m. May 21. Register at www.piecenter.com/easy-as-pie/. The survey findings are available at www.piecenter.com/immigration.


Writer: Mickie Anderson, mickiea@ufl.edu

Sources: Alexa Lamm, alamm@ufl.edu

Jack Payne, jackpayne@ufl.edu

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