UF/IFAS Okeechobee County Extension Service

458 Highway 98 North

Okeechobee, FL 34972-2578

Phone: (863) 763-6469

E- mail: dfculbert@ifas.ufl.edu

May 12, 2004

Feature Article - for release the week of May 16, 2004

Dan Culbert - Extension Horticulture Agent

Beware of "S.O.D."

While our area of the state is know for its extensive, valuable pastures, many acres of Florida are marked by their majestic oaks.  Recently, a disease found in California has moved closer to the Sunshine State, and if it moves in for good, it may dramatically change our forests and landscapes - forever.

Today's column urges everyone to take a look at recently purchased landscape plants - and report any suspicious symptoms to our office.  Your cooperation will save you money, time, and preserve our landscapes and forests.

"S.O.D." has nothing to do with grass - it stands for Sudden Oak Death, a relatively new and deadly disease of trees and plants that may pose significant risks to Florida.  Because the fungus-like pathogen can kill some species of oak trees but not others, scientists don't know if it would have the same devastating effect on Florida oaks as it has had in California oaks.

This disease does not affect humans or other animals.  But, it can mean death to oaks and a few other woody plants.  First - a little bit about oak trees: there are two large families of these magnificent plants, the red oaks and the white oaks. They differ in the amount of time it takes for the acorns to mature (whites take one year, reds take two) and if the leaves are with rounded (white oaks) or spine-tipped (red oak) lobes on the leaves.

Red oaks in California are susceptible to S.O.D.  Infection will kill these trees, but it's speed changes with different species of oaks.  While a few Florida oaks are in the red oak group, the revered southern live oak is in the white oak group.  Scientists are hopeful that our Live oaks will not be affected.  They predict this is so because species in the white oak group are not affected by S.O.D. in California.  However, no one knows for sure at this point.

Other plants can host the fungus, and transfer it to oaks.  Hosts may have symptoms and sometimes may also die from this disease. For example, camellias exhibit leaf spots, defoliation, and stem dieback. In some cases the pathogen infects hosts but does not produce noticeable symptoms for considerable amounts of time.  Because of this, the disease can be difficult to diagnosis.

In the past year and a half, diseased camellias have been introduced unknowingly into Florida from California nurseries. Two nurseries are known to have shipped host camellias to Florida: Monrovia Nursery in Azusa, California shipped wholesale plants to several nurseries for resale, and Specialty Plants, Inc. in San Marcos, California which ships plants directly to customers.

Though many of the diseased plants were recognized and destroyed before they left Florida nurseries, it is possible that some were planted into Florida landscapes. This is where your help is urgently needed.

UF/IFAS and FDACS are working with Master Gardeners and the public to identify any plants that show symptoms of S.O.D.  If diseased plants are found, they will be evaluated for how they may have spread the pathogen.  UF/IFAS and FDACS are seeking to quickly identify potentially infected plants before the pathogen spreads to other plants.  The ultimate goal is to prevent the pathogen from escaping and becoming established in the Florida environment.

 

The most likely kinds of plants that may be infected include camellias, rhododendrons, azaleas and viburnums purchased in 2003 or 2004 that appear to be diseased.  In our area, azaleas and viburnums are the likely ones to look at, but if you know of property owners in North Florida, please alert them to this situation as well.

S.O.D. symptoms may include leaf spots, stem dieback, or overall wilting and death.  Our office can screen samples and will send potentially diseased material for diagnosis of the disease and identification of the pathogen.  Please call first before you bring them in!

If you planted a camellia, azalea, rhododendron, or viburnum in 2003 or 2004 that originated from Monrovia or other California nurseries, or if your woody plants appear to have S.O.D. symptoms such as leaf spots or twig dieback, contact our extension office to get more information on whether a sample should be submitted for testing.  Those plants at highest risk are Monrovia plants that originated in California.

The Florida nursery industry is cooperating extensively with FDACS in continuing efforts to survey for and eradicate any diseased plants introduced into Florida nurseries. Regulations are now in place to prevent further introduction of diseased material from California. Cooperation of everyone is crucial to identify diseased plants should they inadvertently be introduced.

In addition, research is needed to determine which plants can host the disease and how far the disease can spread in Florida. We hope that these steps will prevent the pathogen from being established in Florida. Should the pathogen begin to spread to other plants, timely research can slow or stop the spread of this disease.

For more information on S.O.D. including documents showing symptoms of the disease on various hosts, visit: http://spdn.ifas.ufl.edu/Pest_alert.html. For a bulletin on this disease or to report symptoms of S.O.D., contact our Extension office at okeechobee@ifas.ufl.edu, or stop by our office at 458 Hwy 98 North in Okeechobee.  Master Gardeners can answer your questions about your Florida Yard - call or visit them on Tuesday afternoons here at our office.  Our phone number is (863) 763-6469, and visit our webpage at http://okeechobee.ifas.ufl.edu.

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Trade names, where used, are given for the purpose of providing specific information. They do not constitute an endorsement or guarantee of products named, nor does it imply criticism of products not named. The Florida Cooperative Extension Service - Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research, educational information, and other services to individuals and institutions that function without regard to race, color, sex, age, handicap, or national origin. Florida Cooperative Extension Service / IFAS /University of Florida. Larry A. Arrington, Acting Dean.  Last update: 05/17/2004 .  This page is maintained by Dan Culbert  Hit Counter