How Scientists Identify Viruses

Florida Department of Agriculture and Consumer Servics
Division of Plant Industry

Modern Science Tracks Down Viruses

Viruses are microbes — complicated assemblies of molecules that include proteins, nucleic acids, lipids and carbohydrates. They are not living things; they can do nothing on their own. In order to multiply, they must enter a living cell. Once they infect a living body, they can cause disease.

Plants, like other living things, including you and me, are susceptible to virus infections. Plant pathologists have standard tests that enable them to know when viruses are present. Human doctors and plant doctors, in fact, share many of the standard tests. Often, one type of test can tell them what they need to know, but many times they will employ a combination of tests before reaching a conclusion. Most techniques let pathologists infer the presence of a particular virus; only one, electron microscopy, lets them actually see virus particles.

A first step in detecting a virus might be to look for Inclusions, which are round, oval or irregular-shaped bodies in the cytoplasm and nucleus of cells that indicate the presence of a virus. Plant pathologists use stains when they look for viral inclusions. Different viruses stain differently, and that helps in diagnosis. The location of the inclusion also helps to narrow down the type of virus infecting the plant. While many inclusions are found in the epidermis, others can only be found in vascular tissue or in the nucleus of cells.

Host range inoculations are another technique that help identify viruses. Over the years, plant virologists have inoculated viruses to so many different plants that, by now, they have lists of susceptible and insusceptible plants for each known virus. Pathologists can grind a sample of an infected plant in a buffer, using a mortar and pestle, then manually inoculate plants. They can then compare the plants that become infected with the list of plants susceptible to a suspected virus. A pathologist might get another clue from comparing the host range of the unknown virus with that of a known virus.

An Electron Micrograph of a Flexuous Rod Virus (courtesy of M. Petersen)

Electron microscopy provides the only way researchers can actually see virus particles. Sap from plants that may be infected can be prepared and put into the electron microscope and examined for virus particles.The particles exhibit several basic shapes, enabling plant pathologists to narrow down the type of virus present. Researchers can also fix and thinly section plant tissue for viewing under the EM and their trained eyes can recognize virus particles that may be present.

Serological testing involves purifying and injecting a virus into a mammal, such as a rabbit. The inoculated animal will produce antibodies that coat the virus with proteins. Antiserum from the blood can be used to detect plant viruses. In modern labs, the antiserums used are more likely to be produced using molecular techniques.

There are also tests that detect the presence of a virus by finding its nucleic acid (DNA or RNA). Such tests include polymerase chain reaction (PCR) and DNA probes which attach to the sample when the virus is present. Another type of this test uses a gel to detect the double-strained form of replicating of some RNA viruses. When appropriate controls are used, the size of the band on a gel can indicate the type of virus that is present.

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Maybe you’re wondering how viral infections differ from fungal and bacterial infections. Say tuned!

Traveling for Memorial Day? Here’s a Timely Warning: Don’t Transport Firewood!

Florida Department of Agriculture and Consumer Services
Division of Plant Industry

With Memorial Day approaching, Wisconsin Governor Scott Walker has declared this week Emerald Ash Borer Awareness Week. The invasive pest has infected thirteen counties in that state. It burrows into the bark of ash trees, slowly killing them. State agriculture officials say it’s likely the infestation resulted from the pest’s being transported into the area.

Although it is not known to currently infest Florida, the emerald ash borer does concern Florida agriculure authorities.

GovernorWalker is offering travelers the same advice the Florida Department of Agriculture and Consumer Services Division of Plant Industry has long proffered to Florida visitors: Buy firewood at campsites or from a state-certified firewood vendor instead of transporting it from home.

Toothpick-shaped strings of compacted ambrosia beetle sawdust on redbay.

Here in Florida, agricultural officials are working to keep the emerald ash borer out of the sunshine state as they continue to battle the redbay ambrosia beetle, which transmits a fungus that causes laurel wilt disease. The disease is killing avocado and other trees in the laurel family.

Signs of the disease include:

• Toothpick-like tubes or piles of fine sawdust on the bark
• Drooping foliage with a reddish or purplish discoloration
• Black discoloration on the sapwood surface

Because the redbay ambrosia beetle threatens the state’s valuable avocado industry, FDACS/DPI continues to promote the “Save the Guac” campaign. Key points of the campaign – important for travelers to note as Memorial Day weekend approaches, include:

• Use local firewood or firewood from a  certified firewood vendor only.
• Don’t move unprocessed wood, as it can transfer harmful insects and diseases.
• Don’t transport host trees unless they were purchased from a registered nursery.

See an educational video on laurel wilt in Florida here.

DPI Diary May 17

This edition of DPI Diary covers the two-week period from May 4 through May 17.

Gainesville Health Fair was a hit

This year the Department of Agriculture and Consumer Services partnered with Shands Health Care and the University of Florida for the 2013 Health and Safety Fair. Employees were encouraged to attend and participate in the more than 50 medical screenings and educational displays at the Hilton Hotel and Convention Center in Gainesville. Attendees entered the hall by walking through a giant colon that graphically highlighted  polyps, cancers and other issues for which individuals should be screened. Members of the DPI staff manned displays and offered presentations that highlighted biting insects, poisonous plants, eating healthy “Fresh from Florida” food, apiary and dairy. Botanist Dr. Patti Anderson conducted a session on poisonous plants that included live specimens of poison ivy, poison oak and poison sumac.

Officials laud Coca-Cola plan to invest in Florida citrus industry

The announcement by Coca-Cola Co. that it will spend $2 billion to support the planting of 25,000 acres of new orange groves in Florida, represents a major investment in the Sunshine State’s citrus industry. Coca-Cola will buy fruit from two growers: Peace River Citrus Products in Vero Beach and Cutrale Citrus, one of Brazil’s top growers and juice processors. Cutrale Citrus’ entrance to Florida as a grower is significant, said Florida Agriculture Commissioner Adam Putnam. “The fact that one of the dominant Brazilian players will now have an ownership stake in actual production in Florida is a tremendous development,” Putnam said.

“Don’t Pack a Pest” Partners meet in Washington, D.C.

Division of Plant Industry Director Richard Gaskalla, Director of Public Information Denise Feiber and Public Information Specialist Ellen Dyck traveled to Washington, D.C. last week for a planning session with the agencies that are our partners in the Travelers “Don’t Pack a Pest” Program. The program encourages travelers to declare all agricultural items in their luggage. It is a joint effort of the Florida Department of Agriculture and Consumer Services (FDACS), USDA Animal and Plant Health Inspection Service (APHIS) and Department of Homeland Security Customs and Border Protection (CBP). The “Don’t Pack a Pest” message is delivered via signage at international airports and cruise ports, billboards along Florida highways and videos playing at 20 major airports and aboard American Airlines flights. Last year the program was adopted at two airports in Jamaica. This year the Dominican Republic agreed to join the partnership. 

Don’t eat the giant African land snail

A Miami Herald reporter published a recipe for giant African land snail (GALS) stew from a restaurant in Opa-Locka that serves mainly Nigerian dishes. The restaurateur said her cafe used to serve the dish. Public radio/TV station WLRN published a story that quoted FDACS entomologist Paul E. Skelley, warning of the dangers — including the possibility of contracting meningitis — inherent in consumption of GALS and other snails from the wild. In that article, Skelley also pointed out that it is illegal to import the snails without a permit (and no permits have been issued) or to move GALS from one property to another. The FDACS/DPI GALS eradication team continues to stress: anyone who finds a snail they suspect could be a GALS should avoid handling it without gloves, do not come in contact with its slime, do not eat it, and immediately report it to the FDACS/DPI Helpline, 1-888-397-1517. Inspectors will respond to such calls.

Love Bugs are back

This week DPI social media warned Floridians of the beginning of love bug season and once again attempted to dispel a popular myth. The presence of love bugs here is not the result of an experiment-gone-wrong at the University of Florida. Nor were they a failed method of mosquito control, reared by the United States Department of Agriculture. No, they migrated from Central America into Texas, then spread east all along the Gulf Coast. Today, they can be found throughout Louisiana, Mississippi, Alabama, Florida, Georgia, and South Carolina. Look for he harmless but messy critters to be around until the end of May, then return in September.

Easy way to see FDACS/DPI social media posts

Here’s an easy way to follow us on Twitter, like us on Facebook and follow our division blog. Just go to the division website, http://www.freshfromflorida.com/pi/ look for the “Follow us on the Web” box in the right column, and click on any of the icons.

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This Fair Focused on Health

“Arriba, abajo, adentro.” “A votre santé.” “Nazdravlje,” “Salute.” “Chúc sức khỏe.” “Besalamati.”

“To your Health!”

Ellen Dyck greets visitor to DPI’s booth at the 2013 Health Fair.

This year the Department of Agriculture and Consumer Services partnered with Shands Health Care and the University of Florida for the 2013 Health and Safety Fair. Employees were encouraged to attend and participate in the more than 50 medical screenings and educational displays at the Hilton Hotel and Convention Center in Gainesville.

Attendees entered the hall by walking through a giant colon that graphically (well, not too graphically) showed problems that included polyps and cancers for which individuals should be screened. Members of our staff manned displays and offered presentations that highlighted biting insects, poisonous plants, eating healthy “Fresh from Florida” food, apiary and dairy.

Christina Skitka, DPI information specialist, hosts a display featuring healthy recipes using “Fresh From Florida” food products.

Bees, honey and health were the theme of this DPI booth.

“Leaflets three, let it be.” DPI Botanist Dr. Patti Anderson discussed poisonous plants with live specimens of poison ivy, poison oak and poison sumac.

DPI staff manned displays and offered presentations that highlighted biting insects, preparing and eating healthy “Fresh from Florida” food, apiary and dairy.  Botanist Dr. Patti Anderson conducted a session on poisonous plants that included live specimens of poison ivy, poison oak and poison sumac.

Welcome to Love Bug Season

Florida Department of Agriculture and Consumer Services
Division of Plant Industry

Expect a quick trip on the expressway to leave your car a bespattered mess this month. The love bugs are back. They’ll be ruining your paint job, following you as you walk outside — and smelling just awful when you smash them. Although harmless where human and animal health is concerned, they will invade your personal space and here in the U.S. they are designated an invasive species.

Contrary to popular myth, their presence here was not the result of an experiment-gone-wrong at the University of Florida. Nor were they a failed method of mosquito control, reared by the United States Department of Agriculture. No, they migrated from Central America into Texas, then spread east all along the Gulf Coast. Today, they can be found throughout Louisiana, Mississippi, Alabama, Florida, Georgia, and South Carolina.

The bugs are actually fairly benign where human, animal and plant health is concerned. Pesky as they may be when flying as adults, they’re actually beneficial in their immature stage, according to Tom Fasulo, an extension entomologist with UF’s Institute of Food and Agricultural Sciences. During this stage of their lifecycle, they live on the ground, covered in thatch from newly mowed grass. There they live and eat, supporting plants and the environment by redistributing essential nutrients back into the ground.

A love bug-spattered mess.
Photo courtesy of UF/IFAS.

But in their mature stage, lovebugs are the bane of motorists. They swarm the highways because they are actually attracted to diesel and gasoline exhaust fumes,  hot engines and the vibrations of automobiles. You might want to consider the fact that they tend to fly between 10 a.m. and 4 p.m. when scheduling road trips.

To protect your paint job, wash your car as soon as possible after it gets splattered with lovebugs. Florida natives have discovered many methods of removing lovebugs, including using dryer sheets and Johnson’s Baby Shampoo, Pam cooking spray and lamp oil.

Lovebugs will likely be with us through the month of May. And don’t be complacent when they finally disappear. They’ll  be back in September.

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Letter from Commissioner Putnam

Commissioner Putnam notes the accomplishments of the Florida Legislature following the close of the 2013 session.

 Dear Friends,

On Friday, the Florida Legislature celebrated Sine Die, the end of the 2013 legislative session. This year, there is much to celebrate given all that we accomplished for Florida.

After a $300 million conspiracy was uncovered involving one of the largest purveyors of internet cafes, I worked with Attorney General Pam Bondi and the Florida Legislature to shut down more than 1,000 internet cafes in Florida. Not only were these stores fronts for illegal gambling, but many were also scamming consumers for money while claiming to support charitable causes like veterans and children’s cancer research.

This session, I also worked with Sen. Denise Grimsley and Rep. Travis Hutson to ensure Florida would have an adequate supply of water to meet its future needs. We passed a bill that will establish consistent methodologies in long-term water planning to keep water management districts from applying five different sets of rules. Statewide water policy is critical to Florida’s economic success.

Working with Sen. Bill Montford and Rep. Halsey Bashears, we passed a measure that will help us improve the management of state lands. Our efforts will open more opportunities for public access, increase revenue streams, save taxpayer dollars and protect private property rights.

In addition, Rep. Travis Cummings and Sen. Kelli Stargel helped me pass legislation to better protect consumers from unwanted sales calls and to reduce burdens on charities that receive less than $25,000.

My appreciation goes to Reps. Seth McKeel, Steve Crisafulli and Ben Albritton, along with Sens. Joe Negron and Alan Hays, for their efforts in ensuring the Florida Department of Agriculture and Consumer Services has the resources to further our mission. Florida’s state budget includes funding to support Florida’s fight against citrus greening, a bacterial disease that poses an existential threat to Florida’s $9 billion citrus industry. Florida’s state budget also includes funding to support our efforts to ensure Florida has an adequate supply of water for generations to come, upgrade equipment to enable the Florida Forest Service to protect more than 26 million acres from wildfire and restore oyster reefs in Apalachicola Bay.

Finally, I want to thank Rep. Heather Dawes Fitzenhagen and Sen. Nancy Detert for their unwavering support of our bill to protect children from identity theft. We will continue to work with partners in the Legislature to ensure Florida’s most vulnerable citizens are protected.

I greatly appreciate the hard work of the bill sponsors and the support of all the House and Senate members for my department’s proposals. It has been a successful legislative session and I’m proud of the work we’ve accomplished.

DPI Diary, May 3, 2013

GALS symposium sparks world-wide media blitz

The giant African land snail and efforts to eradicate it from Miami-Dade County were the subjects of a month-long flurry of worldwide media coverage following a symposium on the snail April 9-10 at the Doyle Conner Building in Gainesville. The print, broadcast, electronic and social media coverage reached at least 250 million people. Right now, FDACS/DPI is continuing to focus on reaching the public in Miami-Dade with the message “Look for it! Report It!” An ad is currently screening in some Miami theaters just before feature films. It offers a horrific, close-up view of GALS in an ad styled after trailers for classic 1950s-era horror movies. The ads are appearing at Miami Dolphin 19 with IMAX, Miami Kendall Village Stadium 16, Miami Lakes 17 Cinemas and Miami Movies at the Falls 12. You can view the trailer here.

Commissioner of Agriculture Adam H. Putnam warns consumers to take action to protect their homes from termites and bed bugs.

Warming weather means swarming termites as large numbers of termites leave their colonies in search of new nesting sites, usually March through May, depending on the species. Termites are present throughout Florida. Chances are, anywhere you stand, there are termites nearby. Currently FDACS incident response crews are working in Dania Beach to eradicate colonies of Conehead termites, a particularly invasive species of termite that attack homes and buildings, as well as lumber and wood products and are capable of causing widespread damage. Commissioner Putnam says many homes lack any type of termite protection, even though regular inspection and prevention practices are essential to protecting homes from termite damage.

While termites swarm in the spring, bed bugs can settle into homes anytime throughout the year. FDACS has joined forces with various state, local and private entities to promote public awareness about the prevalence of bed bugs and inform consumers on how to protect themselves from bed bug infestations. Adult bed bugs are normally the size of an apple seed while immature ones are much smaller. Bed bugs are found in the seams of bedding and sofas, backpacks, behind headboards, dressers and various other places. Remove all clutter from your home, which makes finding bed bugs easier. See our blog post, here, for more information on termites and bedbugs.

Verify a pest control company’s license

FDACS regulates and licenses pest control companies and conducts regular inspections to ensure that businesses are in compliance with the rules and regulations that govern pesticides and pest control. To verify if a pest control company is licensed or to file a complaint, call 1-800-HELP-FLA (435-7352), (850)-617-7997 or visit www.flaes.org.

Visit Fresh From Florida at the Epcot International Flower and Garden Festival

Fresh From Florida will be joined by 11 agribusinesses and associations at the Epcot International Flower and Garden Festival May 3-5, 10a-5p in the Festival Center. We hope you’ll come visit!

Where to see the department’s traveling history exhibit

The traveling exhibit featuring 500 years of Florida agricultural history will be on display around the state. Here’s its schedule:

• Polk County Historical Museum: Bartow, May 2 – June 13, 2013
• Sunbelt Ag Expo: Moultrie, Georgia, October 14-17, 2013
• South Florida Fair: West Palm Beach, January 17-February 2, 2014

Statewide advertising campaign promotes fresh local seafood, fruits and vegetables

Dubbed “Fresh from Florida” and largely funded from the state’s financial settlement with energy giant BP after its 2010 Gulf oil spill, the department’s innovative TV-based campaign featrues 15- and 30-second commercials airing in all 10 of the state’s media markets. Given Commissioner Adam Putnam’s goal of more aggressive promotion of fresh local food products, the FDACS team designed a  “push-pull campaign” intended to expand retail distribution by also driving increased consumer demand. (Highlands Today)

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