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United States Department of Agriculture

Agricultural Research Service

Testing
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All accessions in the collection undergo indexing for nine virus and viroid diseases (tristeza and seedling yellows, exocortis, cachexia, psorosis, tatterleaf, concave gum complex and vein enation) and one mycoplasma disease (stubborn). Accessions with positive symptoms are treated by thermotherapy and/or shoot-tip micrografting to eliminate the pathogen(s), then reindexed prior to repropagation. The indexing and virus elimination phases of operations are expected to take several years to complete for the entire collection. Established trees in the collection are reindexed at regular intervals and before distributions.

Last Modified: 7/16/2004