Earl Deveaux
01-17-05, - 10:16 PM
Citrus Canker in The Bahamas
Earl D Deveaux JP
January 2005
The Bahamas Department of Agriculture has reported that Citrus Canker (CC) was positively identified on Abaco, in the Treasure Cay area.
What is it? CC is a highly contagious disease of citrus crops caused by the bacterium Xanthomonas axonopodis pathovar citri. Severe infection can produce a number of effects including defoliation, dieback, badly blemished fruit and premature fruit drop. The disease can also spread to other trees in the citrus family. It is to citrus trees what AIDS is to humans.
There are approximately 3,000 acres of citrus planted around Treasure Cay. An additional 5,000 acres are planted south of Marsh Harbour. Scattered through the island, are many smaller groves ranging from a few trees to a few hundred acres of trees. Grand Bahama has approximately 1,500 acres of Citrus and Andros approximately 1,200. Eleuthera, Long Island and New Providence have scattered groves of 3-10 acres in size; however, there are dooryard citrus trees throughout the country. The Citrus Industry of The Bahamas is estimated to be valued at more than $20 million dollars. The likelihood of the spread of the disease poses an immediate threat to one of the most important sub sectors of The Bahamian agricultural industry.
Where does it occur? The disease most likely originated in South East Asia and has spread worldwide, primarily in warm moist coastal areas-like the Bahamas.
Bahamians and Tourists alike travel throughout the state of Florida and enter The Bahamas from various ports. However, it is significant that Miami, Ft.Lauderdale, Palm Beach, Orlando and Tampa, are the most popular cities for Bahamians and Tourists to visit. These areas are all affected by CC. While the DNA of the strain of canker has not yet been reported; the disease likely came as a result of the hurricanes from last year which hit Florida and The Bahamas. The traveling public must be alerted to the potential consequences of importing infected citrus material. Each time a plant or plant part is carried or moved by a visitor or Bahamian, it heightens the risk of further spread of infestation. Immediate intervention is essential.
Early Detection and spread
Early detection of the disease is vital to reduce the spread and assist in eradication. If a tree is positively identified with CC all citrus trees within 1,900 feet must be destroyed in every direction. The disease spreads easily by wind and rain, when it is most likely to develop. Over short distances, wind-driven rain, air currents, insects, birds, contaminated tools and equipment, used by lawn care workers, and other human movement can spread the canker pathogen. It spreads over longer distances through movement of infected plants, seedlings, propagation material and fruit. Contaminated clothing, tools, harvest and post harvest equipment are also potential sources of infection.
CC does not affect humans, but can ruin lime, orange, grapefruit or tangerine groves. Although not visible for many years, it weakens the trees, eventually leaving them unproductive. The disease should be treated like an epidemic, with all the implications that word entails; intrusive, invasive, direct and sustained intervention.
Management and Quarantine
In areas where CC has been found it is difficult to control. The options available are; spraying with Copper to reduce spread; pruning of affected shoots and the use of wind breaks and finally, complete eradication.
There is no cure for CC. In areas of the world where it is an endemic disease, management involves the use of resistant varieties, windbreaks to hinder the spread of the pathogen and timely application of copper-containing bactericides. These strategies are costly and difficult to sustain. Argentina has adopted these strategies. In the state of Florida, where most Bahamian fruit is exported and packed and from which most of the plant material is imported, the only management option has been determined to be eradication.
Quarantine and eradication are effective in preventing the spread of the disease in newly affected areas. This involves complete destruction of affected trees, bans on citrus planting in affected areas and movement of citrus plants and materials into and out of affected areas. Abaco has already been compromised; therefore a nation wide alert is critical. To illustrate how the disease can spread from island to island; Sandy Point, Abaco and Great Harbour Cay, The Berry Islands are connected by Cat Island Air. Great Harbour Marina and Long Island are connected by ‘The Marina’, used by Long Island fishing boats. Potters Cay is the transit point between Eleuthea, Abaco Andros and Exuma for all manner of traffic.
Eradication involves detection of diseased trees, placing the infected area under strict quarantine, followed by destruction of all diseased and exposed trees within a 1,900 foot radius. It will also require a means of compensation and replacement to be put in place if it is desired to replace the destroyed trees with more resistant varieties following eradication and lifting the quarantine.
What are the costs likely to be if CC is determined to be endemic to The Bahamas?
Can The Bahamas live with CC and what would it cost if it is determined that the disease could not be eradicated? There are a number of cost considerations. The state of Florida has conducted comprehensive cost estimates, which may be used as a basis for evaluating the potential cost for the Bahamas, should living with the disease be considered.
Capital investment of additional spray equipment
Implementing an effective copper-spray control program for citrus canker would require spraying the entire citrus acreage over a two-to three-week period. This spray program will most likely require investment in additional equipment such as air blast sprayers and tractors. Depending on the HP size of the tractor purchased, the first costs would range from $45,000 to $50,000. The PTO- powered airblast sprayer (500-1,000 gallon would cost $25-$30,000. An accompanying 1,000 gallon nurse truck to supply the sprayers would cost an additional $20,000. These costs would have to be replicated on each island, where they are required. If they are not available and manual equipment is employed, then they would have to be replicated many times over, at a greater per acre costs.
Additional cost of copper sprays
Managing Citrus Canker in The Bahamas would require additional copper sprays, above those used to prevent and control other pests and diseases. These additional sprays, to control the spread of canker, would add to the cost of material. In Florida, these costs range from $32 to $59 for processed and fresh fruit. The costs would be at least 50% higher in The Bahamas (transportation, shrinkage, stamp tax, and overhead).
Cost of planting windbreaks for most varieties
Establishing windbreaks would necessitate planting trees in blocks of 10, 20 or 40 acres. Pine trees would be appropriate. However, the windbreaks have the drawback of reducing the yield from the rows near them. In Florida the cost of establishing and maintaining windbreaks annually, range from a low of $7 to a high of $11 per acre depending on the size of the block. The larger block attracts the smallest cost. The revenue loss from the blocks is estimated at $39-$54 per acre.
The value of possible loss of fruit due to citrus canker infestation
If the disease becomes endemic, the more susceptible varieties (Hamlin oranges and grapefruit) would suffer the highest fruit droppage. The loss of fruit is estimated to range from 5%-10%. If the spray programs are improperly applied then fruit loss from early droppage could increase to 30%. The cost of fruit droppage could range from $30-$160 per acre, depending on the variety.
The cost of additional inspection for fresh export certification
Citrus exports from The Bahamas are to agriculture what lobster exports are to fisheries. They account for over 90% of total exports of agricultural goods, excluding marine products. Note that Abaco, Andros, Grand Bahama export an estimated 1,000 bushels per acre annually (close to 6 million boxes equivalent). In order to maintain exports there would be a need for increased inspection for export certification. The Bahamas would have to prove to importing countries that the fruit it is exporting is certified free of citrus canker.
Additional sanitation costs at grove site, harvesting, packinghouse and juice processing plants.
In addition to the cost of inspection for export certification, growers would have to invest in inspection costs to certify that their groves and fruit are free of canker. A certification program would have to be established. This program would likely only permit the export of fruit to Europe, similar to Argentina. The cost would be significant. An eight member team in Florida can inspect 120 acres in an eight hour day. The task must be completed three times before harvests. In addition the fruit would have to be inspected and certified, once picked. These costs together, would add $80-$90 per acre to the cost of producing and marketing the fruit.
If the Bahamas had to manage and live with CC, costs would increase to the grower and the consumer. Lost revenue to farmers would likely result from establishing windbreaks and additional loss of fruit. Also to continue to export the fruit would require additional inspection and certification. This oversight would add to the cost of the fruit as well.
Conclusion
The Bahamas must first complete a needs assessment to determine the policy options. Eradicate? Or treat the disease as endemic and implement programs similar to what has been done in Argentina, where the disease is endemic? Such an option would require The Bahamas to review its trade in this significant export commodity as it will likely result in the Country being banned from trading fresh fruit with The United States.
Where would the Bahamas get help? The Bahamas is a small, island nation, with limited human and financial resources to combat such a devastating disease, over such a porous and geographically dispersed area. However, the risk of the spread of the disease is such that it is in our and our neighbors’ interest that it be eradicated from The Bahamas. The Bahamas could source technical and financial support for the Department of Agriculture through the Food and Agricultural Organization (FAO). As well, the Inter American Institute for Cooperation in Agriculture (IICA) would be a source of technical and financial support. The State of Florida, the United States Department of Agriculture (USDA).Technical assistance from Argentina, Brazil and Australia would also add appreciable expertise to combating and eliminating the disease and establishing a means to prevent further contamination.
However, resources would dictate response. The outbreak requires an immediate response. The disease spreads far and quickly. Containment is the first urgent priority. The areas infected should be under quarantine. No citrus fruits trees or plant parts should be moved from the quarantine areas. The Island of Abaco should be under quarantine. No Citrus trees should be planted in the quarantine area. No potted citrus should be kept in the quarantine area unless it is in a registered nursery. All citrus nurseries should be registered and certified. For the other islands a rigorous protocol of inspection should be implemented. The spread of the disease must be detected early and contained to prevent further contamination. The management option best for the Bahamas is eradication.
Earl D Deveaux JP
January 2005
The Bahamas Department of Agriculture has reported that Citrus Canker (CC) was positively identified on Abaco, in the Treasure Cay area.
What is it? CC is a highly contagious disease of citrus crops caused by the bacterium Xanthomonas axonopodis pathovar citri. Severe infection can produce a number of effects including defoliation, dieback, badly blemished fruit and premature fruit drop. The disease can also spread to other trees in the citrus family. It is to citrus trees what AIDS is to humans.
There are approximately 3,000 acres of citrus planted around Treasure Cay. An additional 5,000 acres are planted south of Marsh Harbour. Scattered through the island, are many smaller groves ranging from a few trees to a few hundred acres of trees. Grand Bahama has approximately 1,500 acres of Citrus and Andros approximately 1,200. Eleuthera, Long Island and New Providence have scattered groves of 3-10 acres in size; however, there are dooryard citrus trees throughout the country. The Citrus Industry of The Bahamas is estimated to be valued at more than $20 million dollars. The likelihood of the spread of the disease poses an immediate threat to one of the most important sub sectors of The Bahamian agricultural industry.
Where does it occur? The disease most likely originated in South East Asia and has spread worldwide, primarily in warm moist coastal areas-like the Bahamas.
Bahamians and Tourists alike travel throughout the state of Florida and enter The Bahamas from various ports. However, it is significant that Miami, Ft.Lauderdale, Palm Beach, Orlando and Tampa, are the most popular cities for Bahamians and Tourists to visit. These areas are all affected by CC. While the DNA of the strain of canker has not yet been reported; the disease likely came as a result of the hurricanes from last year which hit Florida and The Bahamas. The traveling public must be alerted to the potential consequences of importing infected citrus material. Each time a plant or plant part is carried or moved by a visitor or Bahamian, it heightens the risk of further spread of infestation. Immediate intervention is essential.
Early Detection and spread
Early detection of the disease is vital to reduce the spread and assist in eradication. If a tree is positively identified with CC all citrus trees within 1,900 feet must be destroyed in every direction. The disease spreads easily by wind and rain, when it is most likely to develop. Over short distances, wind-driven rain, air currents, insects, birds, contaminated tools and equipment, used by lawn care workers, and other human movement can spread the canker pathogen. It spreads over longer distances through movement of infected plants, seedlings, propagation material and fruit. Contaminated clothing, tools, harvest and post harvest equipment are also potential sources of infection.
CC does not affect humans, but can ruin lime, orange, grapefruit or tangerine groves. Although not visible for many years, it weakens the trees, eventually leaving them unproductive. The disease should be treated like an epidemic, with all the implications that word entails; intrusive, invasive, direct and sustained intervention.
Management and Quarantine
In areas where CC has been found it is difficult to control. The options available are; spraying with Copper to reduce spread; pruning of affected shoots and the use of wind breaks and finally, complete eradication.
There is no cure for CC. In areas of the world where it is an endemic disease, management involves the use of resistant varieties, windbreaks to hinder the spread of the pathogen and timely application of copper-containing bactericides. These strategies are costly and difficult to sustain. Argentina has adopted these strategies. In the state of Florida, where most Bahamian fruit is exported and packed and from which most of the plant material is imported, the only management option has been determined to be eradication.
Quarantine and eradication are effective in preventing the spread of the disease in newly affected areas. This involves complete destruction of affected trees, bans on citrus planting in affected areas and movement of citrus plants and materials into and out of affected areas. Abaco has already been compromised; therefore a nation wide alert is critical. To illustrate how the disease can spread from island to island; Sandy Point, Abaco and Great Harbour Cay, The Berry Islands are connected by Cat Island Air. Great Harbour Marina and Long Island are connected by ‘The Marina’, used by Long Island fishing boats. Potters Cay is the transit point between Eleuthea, Abaco Andros and Exuma for all manner of traffic.
Eradication involves detection of diseased trees, placing the infected area under strict quarantine, followed by destruction of all diseased and exposed trees within a 1,900 foot radius. It will also require a means of compensation and replacement to be put in place if it is desired to replace the destroyed trees with more resistant varieties following eradication and lifting the quarantine.
What are the costs likely to be if CC is determined to be endemic to The Bahamas?
Can The Bahamas live with CC and what would it cost if it is determined that the disease could not be eradicated? There are a number of cost considerations. The state of Florida has conducted comprehensive cost estimates, which may be used as a basis for evaluating the potential cost for the Bahamas, should living with the disease be considered.
Capital investment of additional spray equipment
Implementing an effective copper-spray control program for citrus canker would require spraying the entire citrus acreage over a two-to three-week period. This spray program will most likely require investment in additional equipment such as air blast sprayers and tractors. Depending on the HP size of the tractor purchased, the first costs would range from $45,000 to $50,000. The PTO- powered airblast sprayer (500-1,000 gallon would cost $25-$30,000. An accompanying 1,000 gallon nurse truck to supply the sprayers would cost an additional $20,000. These costs would have to be replicated on each island, where they are required. If they are not available and manual equipment is employed, then they would have to be replicated many times over, at a greater per acre costs.
Additional cost of copper sprays
Managing Citrus Canker in The Bahamas would require additional copper sprays, above those used to prevent and control other pests and diseases. These additional sprays, to control the spread of canker, would add to the cost of material. In Florida, these costs range from $32 to $59 for processed and fresh fruit. The costs would be at least 50% higher in The Bahamas (transportation, shrinkage, stamp tax, and overhead).
Cost of planting windbreaks for most varieties
Establishing windbreaks would necessitate planting trees in blocks of 10, 20 or 40 acres. Pine trees would be appropriate. However, the windbreaks have the drawback of reducing the yield from the rows near them. In Florida the cost of establishing and maintaining windbreaks annually, range from a low of $7 to a high of $11 per acre depending on the size of the block. The larger block attracts the smallest cost. The revenue loss from the blocks is estimated at $39-$54 per acre.
The value of possible loss of fruit due to citrus canker infestation
If the disease becomes endemic, the more susceptible varieties (Hamlin oranges and grapefruit) would suffer the highest fruit droppage. The loss of fruit is estimated to range from 5%-10%. If the spray programs are improperly applied then fruit loss from early droppage could increase to 30%. The cost of fruit droppage could range from $30-$160 per acre, depending on the variety.
The cost of additional inspection for fresh export certification
Citrus exports from The Bahamas are to agriculture what lobster exports are to fisheries. They account for over 90% of total exports of agricultural goods, excluding marine products. Note that Abaco, Andros, Grand Bahama export an estimated 1,000 bushels per acre annually (close to 6 million boxes equivalent). In order to maintain exports there would be a need for increased inspection for export certification. The Bahamas would have to prove to importing countries that the fruit it is exporting is certified free of citrus canker.
Additional sanitation costs at grove site, harvesting, packinghouse and juice processing plants.
In addition to the cost of inspection for export certification, growers would have to invest in inspection costs to certify that their groves and fruit are free of canker. A certification program would have to be established. This program would likely only permit the export of fruit to Europe, similar to Argentina. The cost would be significant. An eight member team in Florida can inspect 120 acres in an eight hour day. The task must be completed three times before harvests. In addition the fruit would have to be inspected and certified, once picked. These costs together, would add $80-$90 per acre to the cost of producing and marketing the fruit.
If the Bahamas had to manage and live with CC, costs would increase to the grower and the consumer. Lost revenue to farmers would likely result from establishing windbreaks and additional loss of fruit. Also to continue to export the fruit would require additional inspection and certification. This oversight would add to the cost of the fruit as well.
Conclusion
The Bahamas must first complete a needs assessment to determine the policy options. Eradicate? Or treat the disease as endemic and implement programs similar to what has been done in Argentina, where the disease is endemic? Such an option would require The Bahamas to review its trade in this significant export commodity as it will likely result in the Country being banned from trading fresh fruit with The United States.
Where would the Bahamas get help? The Bahamas is a small, island nation, with limited human and financial resources to combat such a devastating disease, over such a porous and geographically dispersed area. However, the risk of the spread of the disease is such that it is in our and our neighbors’ interest that it be eradicated from The Bahamas. The Bahamas could source technical and financial support for the Department of Agriculture through the Food and Agricultural Organization (FAO). As well, the Inter American Institute for Cooperation in Agriculture (IICA) would be a source of technical and financial support. The State of Florida, the United States Department of Agriculture (USDA).Technical assistance from Argentina, Brazil and Australia would also add appreciable expertise to combating and eliminating the disease and establishing a means to prevent further contamination.
However, resources would dictate response. The outbreak requires an immediate response. The disease spreads far and quickly. Containment is the first urgent priority. The areas infected should be under quarantine. No citrus fruits trees or plant parts should be moved from the quarantine areas. The Island of Abaco should be under quarantine. No Citrus trees should be planted in the quarantine area. No potted citrus should be kept in the quarantine area unless it is in a registered nursery. All citrus nurseries should be registered and certified. For the other islands a rigorous protocol of inspection should be implemented. The spread of the disease must be detected early and contained to prevent further contamination. The management option best for the Bahamas is eradication.