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Title: FIRST REPORT OF RAVENELIA SPEGAZZINIANA ON ACACIA FARNESIANA FROM BRAZIL

Author
item AVANZATO, M - BRAZIL
item BORGES DA SILVEIRA, R - BRAZIL
item Hernandez, Jose

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/18/2006
Publication Date: 7/17/2006
Citation: Avanzato, M.V., Borges da Silveira, R.M., Hernández, J.R. 2006. First report of Ravenelia spegazziniana on Acacia farnesiana from Brazil. Plant Disease 90(8):1109.

Interpretive Summary: Rust fungi are a very large and diverse group of parasites that attack plants and can be used as biological control agents of noxious weeds. Accurate knowledge about the distribution of rust fungi is important for discovering and identifying potential rust biological control agents. Sweet acacia, also known as cassie, is a source of perfume and is used for fuel in tropical places but it considered a noxious weed in the southern United States. In this research a rust fungus was discovered for the first time in Brazil causing disease on sweet acacia. This research may be useful to plant pathologists who are searching for biological agents to control this invasive weedy plant.

Technical Abstract: Leaves, branches and fruits of Acacia farnesiana (L.) Willd. (Fabaceae) with conspicuous cinnamon brown sori, were collected at the surrounding areas of the Panteón da Liberdade e da Democracia, Brasilia, Brazil, on 5 August 2005. Uredinia and telia were observed in the symptomatic areas. The uredinia were small on leaflets and rachis, and on pods in confluent groups up to 1 cm diam., subcuticular becoming erumpent, cinnamon brown; paraphyses mostly clavate, colorless. Urediniospores are 17-28 × 12-16 µm, ellipsoid to obovoid, wall 1.5-2 µm thick at sides, 2-3 µm at the apex, cinnamon brown, with hub and spoke patter of ornamentation, pores in two bands of 4 each above and bellow the equator. Telia are small, erumpent, on rachis and small branches, lustrous dark cinnamon brown. Teliospores are 84-100 × 65-90 µm diam, chestnut brown, (4) 5-6 probasidial cells across, smooth; cysts globoid, same number as peripheral probasidial cells; pedicel colorless, multihyphal, deciduous. The rust was identified as Ravenelia spegazziniana J.C. Lindq., based on comparison with specimens deposited at Instituto Spegazzini (LPS) and the U.S. National Fungus Collection (BPI), as well as with published descriptions. Ravenelia spegazziniana has been reported on species of Acacia from Central, North, South America and Hawaii. Acacia farnesiana is native to tropical America, but naturalized and cultivated all over the world as fuel wood and for its flowers used in the perfume industry, and became invasive in disturbed areas in some Pacific islands. In Federal District (DF), Brasilia, Acacia farnesiana is commonly used in urban forestation as an ornamental and shade tree. To our knowledge this is the first report of Ravenelia spegazziniana in Brazil. The voucher specimen has been deposited in the herbarium of the Faculty of Biology of Porto Alegre from the Universidade Federal do Rio Grande do Sul as ICN 139085.