Citrus diseases with global ramifications including citrus canker and huanglongbing.

Abstract Although there are a number of diseases that plague citrus production worldwide, two bacterial diseases are particularly problematic. Both are of Asian origin and currently cause severe economic damage: Asiatic citrus canker (ACC) and citrus huanglongbing (HLB). Although ACC has been found in the Western Hemisphere since the early 1900s, HLB was only discovered in 2004. ACC causes foliar, fruit and twig lesions that reduce marketability, can result in significant crop loss, and restrict international trade with areas where the disease has not yet been introduced or become endemic. While ACC has been the impetus for eradication programmes in several countries, only those conducted to combat limited outbreaks have been successful. The costs for 'living with ACC' in Florida including additional bactericidal sprays and quarantine inspections for fresh fruit range from 10 to 20% depending on cultivar susceptibility and market destination of the fruit. By comparison citrus HLB, the most severe of all known citrus diseases has increased production costs by 50-60%. The disease is vectored by the Asian citrus psyllid and was first recognized in India about 150 years ago. HLB has spread throughout most of the citrus producing areas of the world with the exception of the Mediterranean. Worldwide, nowhere that HLB exists, is it under adequate control. Extensive research is underway especially in the newly infected Western hemisphere countries in an attempt to discover and deploy effective control measures for HLB. The presence of these diseases poses an imminent threat of economic survival for affected citrus industries.