Management Challenges Posed by Citrus Canker for Production of Highly Susceptible Grapefruit in Florida
Grapefruit is the most important fresh citrus species grown in Florida, but also the most canker susceptible. The end of the canker eradication campaign in January 2006 and the quarantine imposed on the state had an immediate impact on fresh fruit shipments from Florida to domestic and foreign markets. Presently, shipment to citrus-producing states is prohibited even if fruit show no symptoms. New regulations allow asymptomatic fruit to be shipped to non-citrus-producing states regardless of canker presence in the grove. Inspections can be used to keep symptomatic fruit out of packed cartons when fruit originates from canker-exposed groves. However, if canker incidence on fruits in a block is greater than 2％ -5％ , the Argentine experience indicates that it will be difficult to eliminate all canker-affected fruit by culling in the packinghouse. No highly effective disease suppression strategies exist for grapefruit grown in wet, subtropical areas. In South America, integrated programs for prevention and control of canker on less susceptible sweet oranges, tangerines, and lemons have been successful. These areas combine the use of more field-resistant cultivars and multiple copper sprays in conjunction with windbreaks and leafminer control. Copper-based bactericides are necessary for protection of grapefruit as they grow from 2cm in diameter to full expansion. To protect fruit, copper must be applied every 21 days which can require 10 or more spray applications per season. The effectiveness of copper is overcome by wind-blown rain in excess of 8 m/sec that occurs frequently during the tropical weather season in Florida. Copper has other possible disadvantages including phytotoxicity to the peel, the development of resistance in xanthomonad populations and the accumulation of copper in soils with potential environmental impacts. Streptomycin is an alternative contact bactericide found to be effective, but the high cost and risk of development of antibiotic resistance in bacterial populations will limit its use in spray programs.
Xanthomonas citri. subsp Canker epidemic Marketing of fresh fruit Spray trials in Florida
James H. Graham Beatriz Stein Rui P. Leite Jr.
University of Florida, IF AS, Citrus Research and Education Center, Lake Alfred, FL 33850, USA Instituto Agrondmico do Parand, Londrina, Parand, Brazil
国际会议
11th International Citrus Congress(第11届国际柑橘大会)
武汉
英文
1055-1059
2008-10-01（万方平台首次上网日期，不代表论文的发表时间）