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United States Department of Agriculture

Agricultural Research Service

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 Citrus Facts


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Citrus Facts

  • Every variety of citrus you eat, whether a Navel or Valencia orange, a white or red grapefruit, a juicy lemon or lime etc. was found by " accident " by someone eating a fruit from some tree, somewhere in the world. The fruit on a particular branch of a tree was superior to the fruit that the farmer was intending to produce.
  • Citrus varieties you eat are grafted clones from that original tree. This is done by grafting buds from the tree whose fruits are desirable onto seedling rootstocks that are used for horticultural reasons.


T bud graft into a citrus stemChip bud graft into citrus stem

  • As a result all fruit of a given variety are genetically identical, and seedlings grown from them will not be the same variety.
  • Resistance to pathogens and pests can't be bred into citrus for this reason and others.
  • Citrus diseases and insect pests are an increasing problem for citrus growers worldwide as a result of the global economy and ease of international travel.
  • Diseases and insect pests can be introduced into countries that previously did not have them when people bring bud wood home with them to propagate after they visit foreign countries. This can be done for commercial reasons or to 'remember grandmother'. Either way it is illegal. For more information about plant importation Contact the Animal and Plant Health Inspection Service
  • The citrus industry in the US is under very severe disease and insect pest pressure because people have illegally propagated trees in this manner. The citrus industry is fighting back. Find out how by visiting the Citrus Research and Development Foundation and the Citrus Research Board websites.
  • The presence of citrus trees grown legally by the public on their own property and for their personal use complicates every control strategy for citrus diseases.

orange line

For more information about citrus pathogens please contact Dr. John Hartung

For more information concerning growing citrus please contact Cristina Paul

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Florida Juice Commission*
University of Florida*
Sunkist kid's stuff*
The Ultimate Citrus Page*
California Citrus Research Board*
Citrus from Down Under- Citrus Australia *
Texas Citrus*
* Goes to non-federal site

Last Modified: 8/13/2016
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