GAINESVILLE, Fla. \u2014 Canker topped the list of worries for the Florida citrus industry until citrus greening \u2013 described as the world\u2019s most serious citrus disease \u2013 was found in groves last year.<\/p>\n
\u201cIn the long term, the industry can live with and manage the canker problem, but citrus greening is a fatal disease that\u2019s an even larger threat to the state\u2019s signature crop,\u201d said Harold Browning<\/a>, director of the University of Florida\u2019s <\/a>Citrus Research and Education Center in Lake Alfred<\/a>. \u201cIn other areas of the world where greening is a problem, it has never been successfully eradicated.\u201d<\/p>\n The disease, which slowly weakens and kills all types of citrus trees, causes fruit to become lopsided and taste bitter, making it unusable. Fruit does not develop the desired color, hence the greening name. There is no known cure for the disease, which is on the U.S. Department of Agriculture\u2019s <\/a>select list of threats to plants and wildlife regulated by the Agricultural Bioterrorism Protection Act. Greening does not harm people.<\/p>\n Browning said the fatal bacterial disease is transmitted by the Asian citrus psyllid (Diaphorina citri), a tiny insect that is now widely distributed throughout Florida, and the disease has been found in more than 440 locations in 11 counties. Browning said it\u2019s not practical to eradicate citrus greening, but the spread of the disease can be slowed with an effective integrated pest management program (IPM) that includes limited use of systemic insecticides and beneficial insects that attack the psyllid.<\/p>\n The introduction of a beneficial wasp was the first step in an expanded research program by UF\u2019s Institute of Food and Agricultural Sciences <\/a>to develop a wide range of best management practices to prevent greening from destroying the state\u2019s $9.1 billion citrus industry, Browning said. UF researchers are also developing management programs to combat canker.<\/p>\n Marjorie Hoy<\/a>, a UF professor of entomology<\/a> and biological control expert, said the psyllid was first detected in two South Florida counties in June 1998. At the time, the psyllid was considered to be a significant pest, and although it did not appear to carry the deadly bacterial disease that causes citrus greening, it made establishment of greening more likely if the disease were introduced. Damage caused by the psyllid included stunting of new growth and sooty mold formation on the honeydew produced by the psyllids.<\/p>\n \u201cWhen citrus greening started showing up in citrus trees across the state in September 2005, we knew that that we had a potential disaster on our hands, and that the psyllid was carrying and transmitting the deadly disease,\u201d she said.<\/p>\n