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UF/IFAS study finds simple solution to monitoring major berry pest

Topic(s): Crops, Economics, Pests, Research

Spotted wing drosophila trap in blueberry bushes1

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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 suzukii 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.

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Climate, genetics can affect how long virus-carrying mosquitoes live

Topic(s): Entomology and Nematology, Pests, RECs, Research

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GAINESVILLE, Fla. — It’s just math: The longer a mosquito lives, the better its odds of transmitting disease to humans or animals.

But as it turns out, factors such as the mosquito’s own genetics and the climate it lives in have a big – albeit complicated and not wholly understood – role to play in its lifespan.

University of Florida researchers, hoping to better understand how West Nile virus affects mosquitoes, set up an experiment they outline in the Journal of Vector Ecology’s current issue.

Mosquitoes can transmit any number of pathogens to humans, including protozoan malaria, West Nile, dengue and chikungunya viruses. Malaria cases range between 350 million and 500 million each year, with 1 million to 3 million deaths every year.

In the experiment, UF researchers examined survival rates for mosquitoes from two laboratory-reared colonies, one from Gainesville and one from Vero Beach.

Half of each of the mosquito colonies was fed West Nile virus-infected blood, the other half kept as a control population, and fed blood without the virus.

They divided the groups once more, this time keeping the mosquitoes at two temperatures, one group at 80.6 degrees, the other at 87.8 degrees Fahrenheit – a rather large difference in temperature for cold-blooded insects.

Their findings were both unexpected and illuminating, said Barry Alto, a UF assistant professor of arbovirology based at the Florida Medical Entomology Laboratory in Vero Beach.

“Our results indicate that interactions between mosquitoes and arboviruses are really complex … these things that haven’t really been taken into account previously might make a difference,” said Alto, part of UF’s Institute of Food and Agricultural Sciences.

The researchers found that warmer temperature shortened survival.  Also, for the most part, the Vero Beach mosquitoes lived longer than those from Gainesville, indicating that some groups, or strains, of mosquitoes might just be genetically hardier than others.

They found that in general, the mosquitoes fared better at cooler temperatures.

But they also found that the West Nile virus-carrying mosquitoes from Gainesville fared worse than their counterparts at the hotter temperatures, and to their surprise, that the Vero Beach-bred mosquitoes carrying West Nile virus lived longer than all other groups at the cooler temperature, including control-group mosquitoes not exposed to the virus.

Ingesting virus-infected blood may take a toll on the mosquito’s health, Alto said, but it’s clear that other factors: immune response, genetics and the environment, are also at play and need more study.

“It’s quite complex, there’s a lot of stuff going on here,” Alto said. “But I think the take-home  message is that these viruses, when they’re in mosquitoes, not only can they alter parameters like survivorship that are really important to disease transmission, but they can alter them in non-intuitive ways — sometimes enhancing, sometimes decreasing survivorship, and that those situations arise when you start considering other factors of the environment, like temperature.”

Adding to scientists’ knowledge base of how disease affects insects is key to finding the best ways to limit its spread, Alto said.

“In the most general sense, in order for humans to control disease, we really need to know how the mosquito interacts with these viruses,” he said. “In the absence of a human vaccine, the best way to control any sort of mosquito-borne virus is to control the mosquito. Simply put, if the mosquito doesn’t bite you, you’re not going to get the pathogen.”

Besides Alto, the research team included Stephanie Richards, an assistant professor at East Carolina University; Sheri Anderson, a former graduate student at the Florida Medical Entomology Lab and Cynthia Lord, an associate professor in modeling of vector-borne disease transmission, also of the FMEL. The study was funded by the National Institutes of Health and UF/IFAS.

Contacts:

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

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

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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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With a little help, citizen scientists can be good proxies, research shows

Topic(s): Agriculture, Environment, Families and Consumers, Household Pests, Lawn & Garden, Pests

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GAINESVILLE, Fla. – Anyone can collect ant data as accurately as experts, if they have a bit of guidance and the right tools: cookies, index cards and plastic zip-top bags.

In a joint project between the University of Florida and North Carolina State University called the School of Ants, participants collected the insects at their homes, work or school. Using cookies to lure the insects, they bagged them, froze them, then sent them to labs so that ant experts could identify them and incorporate them into a national ants map.

Researchers at UF and N.C. State examined participants’ errors against mistakes of researchers trained in an N.C. State lab. Data from the two groups were virtually the same. Scientists say the similar findings came because the lay people followed their system.

The finding boosts the field of what’s called citizen science, a rapidly expanding area of data collection, said Andrea Lucky, an assistant scientist in entomology and nematology at UF’s Institute of Food and Agricultural Sciences. Lucky started the School of Ants in 2011, while a postdoctoral researcher at N.C. State, and brought the project with her to UF. The project is still going at both universities.

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UF/IFAS strategies give forest owners, managers disaster-coping methods

Topic(s): Agriculture, Conservation, Forestry, Pests, Weather

Forest strategies

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GAINESVILLE, Fla. – Scientists believe climate change means more erratic weather patterns for the future, and that doesn’t bode well for forests in the Southeastern U.S.

Two things trees don’t need are damaging hurricane-force winds and wildfires, and they believe those climate change-related weather patterns portend more of both.

University of Florida researchers, including postdoctoral research associate Andres Susaeta, built a computer model that simulates various climate scenarios in hopes of minimizing the potentially cataclysmic damage to forests on privately owned forest land.

“Climate change is likely to affect forest productivity and exacerbate the impacts of big disasters on forest ecosystems in the South,” Susaeta said.

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UF/IFAS researchers find chemicals that treat citrus greening in the lab

Topic(s): Agriculture, Citrus, IFAS, Pests, Research
A citrus tree sapling hosts the Asian citrus pyllid, which spreads citrus greening disease through a bacteria it carries.

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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 at UF 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. (more …)

UF/IFAS finding could help farmers stop potato, tomato disease

Topic(s): Crops, Economics, Pests

potato famine photo

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GAINESVILLE, Fla. – A University of Florida scientist has pinpointed Mexico as the origin of the pathogen that caused the 1840s Irish Potato Famine, a finding that may help researchers solve the $6 billion-a-year disease that continues to evolve and torment potato and tomato growers around the world.

A disease called “late blight” killed most of Ireland’s potatoes, while today it costs Florida tomato farmers millions each year in lost yield, unmarketable crop and control expenses.

For more than a century, scientists thought the pathogen that caused late blight originated in Mexico. But a 2007 study contradicted earlier findings, concluding it came from the South American Andes.

UF plant pathology assistant professor Erica Goss wanted to clear up the confusion and after analyzing sequenced genes from four strains of the pathogen, found ancestral relationships among them that point to Mexico as the origin.

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Who’s fooling who? Species communicate, ‘eavesdrop’ and play tricks near infected trees

Topic(s): Citrus, Entomology and Nematology, Pests

GAINESVILLE, Fla. – Four species communicate with and sometimes trick each other around a scent produced by greening-infected citrus trees, a new University of Florida study finds.

Communication between species is common but almost always is described between two or three species, said Lukasz Stelinski, associate professor of entomology and nematology at the Citrus Research and Education Center in Lake Alfred.

Stelinski wanted know how a fourth species, in this case, a wasp, would vary this interaction ─  a probe that may be one of the few cases where species at four levels of the food chain use one odor to communicate with, and exploit, each other.

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Growers play vital role in UF/IFAS organic strawberry study

Topic(s): Crops, Cultivars, Economics, IFAS, Pests

Strawberries.  UF/IFAS Photo by Marisol Amador.

This UF/IFAS file photo shows Florida-grown strawberries.

GAINESVILLE, Fla. – After the first year of a University of Florida study to try to develop new organic strawberry production systems, growers are playing a critical role in setting priorities for the research project’s future.

The study stemmed from several issues strawberry growers face. Rising costs of production and increased imports of strawberries threaten the sustainability of the Florida strawberry industry, one of two major production regions in the nation. Demand for organic strawberries is growing and brings a price premium for growers who can master the art and science of organic strawberry production.

Organic and conventional growers assessed parts of the first year of research, said Mickie Swisher, associate professor of sustainable agriculture in UF’s Department of Family, Youth and Community Sciences and a member of the Institute of Food and Agricultural Sciences.

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A better bedbug trap: Made from household items for about $1

Topic(s): Entomology and Nematology, Environment, Household Pests, New Technology, Pests

Benjamin Hottel, a University of Florida doctoral student in entomology, left, and Phil Koehler, an urban entomology professor, demonstrate how to build a do-it-yourself bedbug trap. They created a method for building an inexpensive trap to help those who

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Bug-Trap

This graphic illustrates how you can make the bedbug interceptor trap.

Video available at: http://bit.ly/1vfXPrL.

GAINESVILLE, Fla. — The contraption seems so simple, yet so clever, like something The Professor might have concocted on “Gilligan’s Island.”

Researchers at the University of Florida’s Institute of Food and Agricultural Sciences have devised a bedbug trap that can be built with household items. All you need are two disposable plastic containers, masking tape and glue, said Phil Koehler, UF/IFAS urban entomology professor. The traps catch and collect the bugs when they try to travel between people and the places where bedbugs hide, he said.

“This concept of trapping works for places where people sleep and need to be protected at those locations,” Koehler said.

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