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ARS Home » Southeast Area » Miami, Florida » Subtropical Horticulture Research » Research » Publications at this Location » Publication #354753

Research Project: Conservation, Evaluation, and Distribution of Sugarcane, Mango, Avocado and Other Subtropical and Tropical Genetic Resources and Associated Data

Location: Subtropical Horticulture Research

Title: Avocado Sunblotch Viroid

item Kuhn, David
item Geering, Andrew - University Of Queensland
item Dixon, Jonathan - Seeka Limited

Submitted to: Viroids and Satellites
Publication Type: Book / Chapter
Publication Acceptance Date: 10/9/2016
Publication Date: 8/1/2017
Citation: Kuhn, D.N., Geering, A., Dixon, J. 2017. Avocado Sunblotch Viroid. In Hadidi, Ahmed, Flores, Ricardo, Palukaitis, Peter, Randles, John. Viroids and Satellites. 1st Edition. Elsevier, London. p 297-305.

Interpretive Summary: Avocado is an important crop in the US with California producing about 90%, Florida about 10% and Texas and Hawaii about 1%. Avocado sunblotch disease caused by Avocado Sunblotch Viroid (ASBVd) is an important pathogen of avocado causing serious yield losses. Most of the ASBVd infected trees are devoid of the visual symptoms of the disease (sunblotched fruit with deep indentations). However, symptomless infected trees have decreased yield and can infect other trees in the groves. This book chapter summarizes the history of ASBVd research including diagnostics and preventative methods. The chapter provides important background information for growers, marketers and researchers in the avocado industry.

Technical Abstract: Avocado sunblotch disease was observed as early as 1914 in the West Indian Gardens Nursery at Altadena, which was owned by Frederick Popenoe, a pioneer of the Californian avocado industry. However, it took until 1928 before an official description of the disease was published, and the symptoms were initially attributed to sunburn. In 1932, graft-transmissibility of the disease was demonstrated, suggesting a viral etiology, and this hypothesis persisted for nearly 50 years until avocado sunblotch viroid (ASBVd) was discovered. As avocado is the only known natural host of ASBVd, it is likely that the viroid originated in the same region as its host, the eastern and central highlands of Mexico, through Guatemala to the Pacific coast of Central America. In 1911, Popenoe organized a collecting mission to Atlixco, Mexico, in search of superior varieties, including the original “Fuerte” plant, which was to become the mainstay of the Californian industry during its first decades. “Fuerte” was among the worst affected varieties and 30-year old “Fuerte-like” trees with sunblotch symptoms were observed near Atlixco in 1948. During the 1930s and 1940s, ASBVd became prevalent in San Diego County, where a little over one-half of the total acreage of avocado trees in California was to be found, and ranked second in importance to Phytophthora cinnamomi as a pathogen. From California, ASBVd was likely transported to many countries in the world like Australia, Israel , and Peru, as new varieties developed there were in strong demand elsewhere.