Florida's production of both food and fiber is under serious threat from emerging pathogens new to this state. Many of Florida's most important agricultural and natural resource industries, including citrus, tomato, strawberry, and tourism are facing the potential of enormous economic losses. By focusing on problems such as citrus diseases (canker, blight, greening), sudden oak death, soybean rust, Pierce's disease of grapes, and human pathogens present in vegetables, fruits, and seafood we can development a research capability prepared to prevent and control outbreaks caused by these pathogens. We need the teaching capability to train the next generation of scientists who will keep these pathogens at bay in the future. And we need the outreach capability to educate the people of Florida on steps they can take to avoid economic losses as growers and to avoid disease from food-borne pathogens as consumers. Florida’s natural and managed landscapes are under treat from pathogens such as sudden oak death which caused massive losses of landscape in peer states such as California.
As Florida has a wide array of temperate, sub-tropical, and tropical ecosystems its diverse agriculture is particularly vulnerable to new pathogens requiring intensive vigilance by IFAS staff. Recent hurricanes have shown how pathogens can appear or reappear from the Caribbean and Latin America simply by being wind-borne. In addition, tourists and commercial plant imports from around the world have the potential to unwittingly carry pathogens to our state from other countries. All of these factors make Florida more susceptible to these diseases than perhaps any other state in the nation and require more intensive research, education, and outreach efforts by IFAS than can now be provided with current resources.
Citrus Greening, or Huanglongbing (HLB), is a serious disease of citrus because it affects all citrus cultivars and causes rapid decline of trees. HLB has seriously affected citrus production in a number of countries in Asia, Africa, the Indian subcontinent and the Arabian Peninsula, and was discovered in Brazil in 2004. HLB is carried to citrus plant by psyllids. When the psyllid is abundant and the environmental conditions are favorable, HLB can rapidly destroy existing groves and prevent commercial production of oranges and other citrus cultivars. Mature trees if infected may decline and become non-productive and young trees that become infected never come into fruit production. In China, the disease was reported to kill young trees in 1-2 years. HLB is difficult to manage and continued production of citrus has proven difficult and expensive in areas where it is widespread. Since HLB is transmitted by the psyllid vector which has been established in Florida and weather conditions are apparently suitable for occurrence of HLB, there is clearly a potential for natural spread now that HLB has been introduced into Florida. Sweet oranges, mandarins, and mandarin hybrids (tangelo) are highly susceptible to HLB. Lemons, grapefruit, pummelos, and sour orange are also affected and are rendered non-productive when infected. Mexican lime, trifoliate orange and some trifoliate orange hybrids are more tolerant and may show only some leaf symptoms. The HLB bacterium also can multiply in Chinese box orange (Severinia buxifolia) and wood apple (Limonia acidissima). Reference:
Prior to 2005, HLB had not been reported in the U.S., Australia or in the Mediterranean Basin. However, this exotic disease has recently been identified in Florida. Current hypotheses for introduction include infected budwood brought into FL by an importer or private citizen. Inspection of imports and baggage may or may not have caught this introduction, since detection is difficult. However, education of the public may have had an impact, and current programs to deal with this introduced disease include public and industry education and outreach.
Q. What is a plant pathogen?
A. A plant pathogen is an organism that causes a disease on a plant. Although relatives of some plant pathogens are human or animal pathogens, most plant pathogens only harm plants.
Q. Why are plant pathogens important?
A. Organisms that cause plant diseases reduce our ability to produce food and support the economy. Everything from citrus to grains to ornamental plants are susceptible to plant diseases. Plant diseases cause billions of dollars worth of direct and indirect losses every year (Citrus Greening example). Emerging plant pathogens require preparation and planned, scientifically-based response to lessen the impact on our farmers and economy.
Q. What can we do about plant diseases?
A. Management of plant diseases includes management of overall plant health. Healthy plants are less likely to get diseases, just like healthy humans. You can help reduce the impact of both emerging and endemic plant pathogens by remembering not to transport unhealthy plant parts or products.
Q. What is the difference between an endemic plant pathogen and an emerging one?
A. An endemic pathogen is one that has become established in a new environment and is no longer possible to eradicate. At that point, response switches from keeping it out or eradicating it to managing it through plant health, antimicrobial chemistries, and monitoring production. An emerging pathogen is one that has not caused a problem in the new environment because it has not been found there before, or one that has changed to become a problem in a place where it has been known to occur, but did not have economic or natural impact.
Location: http://epi.ufl.edu/plant/index.shtml