Prepared by Daniel F. Culbert, County Extension Director
Release: 02/28/99

Our office has started to receive information from the 1997 US Census of Agriculture about our local agricultural inputs to the local economy. It should be to no one's surprise that Citrus is one of the most important economic industries to our county. But a renewed threat has reared its head - Citrus Canker - which could wipe out this industry and countless dooryard fruit trees. Information for today's column comes from University of Florida's Extension Specialists and from an excellent Internet web page from the Florida Department of Agriculture.

The current Canker outbreak in Dade and Broward Counties has become difficult to eradicate because the disease is found in home landscapes in many areas of greater Miami and Fort Lauderdale. There is also evidence that canker has been identified in Manatee County and in the Immokalee area. It is not known to be in the Indian River area at this time - but that may change quickly if a careless visitor from an infected area brings infected fruit or a tree to our area. Dooryard citrus growers have an obligation to become familiar with this disease, to report suspected cases, and to prevent the movement of infected fruit or plants.

Citrus canker causes trees to weaken, lose leaves and drop fruit prematurely. Infected fruit will have visible canker sores which impact the quality of the fruit. Eventually, diseased trees will produce a small, substandard crop. There is no cure for Citrus Canker. The only known control is eradication - cutting down and disposing of trees affected by citrus canker. Florida Department of Agriculture Inspectors are currently visiting every property inside the quarantine area within Dade County, and if found to be infected, trees on the property will have to be cut down. Once the canker has been eradicated and the quarantine lifted, residents of that area can replant citrus trees as soon as federal authorities allow.

WHAT IS CITRUS CANKER?
Citrus canker is a bacterial disease of citrus that causes premature leaf and fruit drop. Citrus canker is highly contagious and can be spread rapidly by:

• windborne rain
• lawnmowers and other landscaping equipment
• animals and birds
• people carrying the infection on their hands or clothing
• moving infected or exposed plants or plant parts

What does citrus canker look like? Symptoms on leaves and fruit are brown, raised lesions surrounded by an oily, water-soaked margin and a yellow ring or halo. Old lesions in leaves may fall out, creating a shot-hole effect. Citrus canker does not harm humans or animals or plant life other than citrus. It affects all types of citrus, including oranges, sour oranges, grapefruit, tangerines, lemons and limes. Canker causes the citrus tree to continually decline in health and fruit production. Ultimately, the tree will produce no fruit at all.

HOW CAN YOU HELP?
Review the description of the symptoms carefully - there are several diseases that look like canker. DO NOT bring samples of suspected canker to our office - it will spread the disease. Instead, call our office and discuss this with our Master Gardeners FIRST. We have some color photos of canker and other citrus plant disease symptoms that you can look at in our office. Canker could easily be confused with Citrus Scab - which is common on tangerines, melanose, or Citrus bacterial spot.

If there is a chance that the symptoms you see are canker, we will give you the phone number of our county's FDACS DPI Plant Inspector, who can come visit your property. PLEASE - there is ONE of him, and 107,000 county residents - so we need to be somewhat sure this is what's going on before we ask him to check it out. But this disease is dangerous so be on the lookout and report any suspected symptoms.

Allow inspectors into your yard to check your citrus trees. If canker is discovered in your property, you can assist by giving the state permission to remove infected trees and do not move any citrus trees, citrus plants or citrus fruit from quarantined areas. If you are going to dispose of any infected citrus plant parts, please double bag them first.

The current eradication effort will not only protect Florida's $3 billion citrus industry, but is also targeted at saving the more than 2 million backyard citrus trees in Dade County that have not yet been affected by canker. Because this disease spreads easily, there is also concern about its impact on backyard citrus trees throughout the state.

Florida Agriculture Commissioner Bob Crawford recently announced the appointment of a 14-member task force to explore the ways and means combat the citrus canker outbreak in Florida. Our local Indian River Citrus League is represented on this task force. You can contact the members of this committee though our office if you have ideas, or your state and federal legislators if you have any strong feelings on this matter.

The Internet address for the state's Citrus Canker web page is doacs.state.fl.us/canker. We can supply you with a paper copy if you do not have a way to view this on a computer. The state also maintains a Citrus Canker help line in Dade County at (305) 598-6988 - this will be a toll call for Indian River residents.

If you need additional information on citrus canker, visit our Master Gardeners, or call or stop by our office. For those with other questions about Florida Yards, our office holds Master Gardener Clinic hours at the Extension office (1028 20th Place, Suite D, Vero Beach) every weekday morning and most afternoons, Wednesday morning at the Sebastian Library, and the second and fourth Saturday of the month at the ELC. Our phone number is 770-5030, and you can leave a message after hours.

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 Indian River County 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. Christine T. Waddill, Dean.