UF/IFAS Okeechobee County Extension Service

458 Highway 98 North

Okeechobee, FL 34972-2578

Phone: (863) 763-6469

E- mail: dfculbert@ifas.ufl.edu

June 29, 2005

Feature Article - for release the week of July 3, 2005

Jack Hebb - Extension Citrus  Agent  and  Daniel F. Culbert, Extension Horticulture Agent

Declare independence from Citrus canker

Okeechobee has now joined that infamous list of counties that is actively battling citrus canker.  According to Florida Department of Agriculture officials, there are now four confirmed cases of the dreaded citrus canker that have been identified in local commercial citrus groves.

This past January our office provided a column from UF/IFAS Citrus Agent  Jack Hebb on how homeowners can assist in the battle against citrus canker.  While it is nothing revolutionary, in order for Florida to declare its independence from citrus canker, everyone must be prepared.  Today’s column will update that information.  With everyone’s help we can become independent of this disease.

Local growers have been afraid that it has just been a matter of time until citrus canker would be discovered in our area.  They are preparing their crews and equipment to deal with this outbreak.  But they need your help.  However, no one is more susceptible to the importation and transfer of this disease than dooryard citrus owners.  Homeowners are usually very proud of the citrus that can be grown in their Florida Yards.

Florida has always had a climate agreeable to growing lots of citrus.  But, our climate has also encouraged certain problems that test a citrus tree’s ability to survive.  Among the list of maladies for citrus survival, there is one that tops the list - citrus canker.

Citrus canker is a highly contagious disease that attacks the fruit, stems, and leaves of citrus.  It also causes lesions on the fruit. The disease is not harmful to humans or animals, but it WILL affect the health and vitality of citrus trees.

Unlike most citrus diseases, which are usually plant-like fungi, citrus canker is a serious bacterial disease. When a plant disease is caused by bacteria, the only ways to control it are to use chemicals to kill the organism, or by sanitation, which means that effected plants must be burned.  Citrus Canker bacteria are microscopic, and can be spread by uncontrollable events such as by wind, rain, or even by wildlife.  There are also other cases where human contact has moved the bacteria into canker-free areas.  The following human activities can move citrus canker from an infected area to unaffected locations:

·        landscaping (trimming, chipping, cutting, or pruning citrus trees)

·        fruit removal (peeling, buying, selling, transporting, picking, etc.).

To prevent the spread of canker bacteria, use approved disinfectants on people and equipment that move into or out of citrus canker infected areas.  To insure that canker bacteria on infected plants are eliminated, all commercial citrus trees within a 1900 feet distance of an infected tree are burned.  In the case of citrus growers, it means the removal of more than 200 acres per infected tree site in contiguous groves. In a neighborhood or subdivision, this would mean the removal of neighboring citrus trees for many blocks. Homeowner trees that must be removed are chipped and disposed by either landfilling or burning the residue.

For homeowners, I recommend the following measures to help control canker:

(1) Don’t bring suspect citrus plants to the office for identification.  If you suspect any part of a citrus tree of has canker, please do not remove the leaves, fruit, or limbs - leave them alone.  Call the citrus canker toll-free helpline at (800) 282-5153 or the Satellite office in Avon Park at 863-314-5900.  The Florida Department of Agriculture officials will promptly respond to your call by sending an inspector to the suspected tree location.   Inspectors will identify themselves and seek your permission to view the tree.  Do Not, and I repeat, Do Not, remove suspicious citrus tree parts and transport them to another location.

(2) If you walk, drive or visit any grove or other property where canker has been identified, you should plan on washing all outer clothing (gardening clothes, gloves, hats etc.) in a hot water cycle with laundry soap immediately following outdoor chores around citrus trees.  Disinfecting your hands can be done by first washing them with soap and water, followed by dipping into a chlorine bleach (sodium hydrochloride) disinfectant solution  of approximately 1 oz. of bleach to 1 gallon of water (a 200 ppm solution).  

(3) Clean all landscape tools (pruning shears, clippers, chain saws, pocket knives, etc.) that have contacted citrus trees.  Use a Clorox-type disinfectant at the rate of about 6 oz. of bleach to 1 gallon of water (about 1200 ppm). Be sure to wash the tools clean of any soil or plant residue before dipping in the bleach solution.  

(4) Have any landscapers who work on your property (yardmen, landscapers, etc. who may work around citrus trees) practice the same measures as listed above.  A specific decontamination suggestions bulletin for landscapers is available.

We encourage all local residents to be on the lookout for suspicious looking lesions on their citrus trees. We need to be alert and aware.  If citrus canker is not eradicated from our state, it could destroy one of Florida’s most important crops, eliminate many jobs and destroy an abundant product that is enjoyed by homeowners and consumers.

I’ve placed a new Citrus Canker page on our Okeechobee website, http://okeechobee.ifas.ufl.edu where you can see photos of canker and find other information.  Key places to get official information are the UF/IUFAS Citrus Canker website, http://canker.ifas.ufl.edu/index.asp, and the Florida Department of Agriculture’s website, http://www.doacs.state.fl.us/pi/canker/.  If you need additional information on citrus canker, please email us at okeechobee@ifas.ufl.edu or call us at 863-763-6469.  Local residents can stop by our office at 458 Hwy 98 North in Okeechobee, and visit our Okeechobee County Master Gardeners on Tuesday afternoons from 1 to 5 PM.  Happy Independence Day!

-30-

University of Florida Citrus Canker Program Website

Florida Department of Agriculture Citrus Canker Website 

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. This page is maintained by Dan Culbert