The use of different baits to isolate phytophthora from stream ecosystems

• Danilo Reis Gonçalves ^[1]
  1. [1] Universidade Federal Rural do Rio de Janeiro

     Universidade Federal Rural do Rio de Janeiro

     Brasil

     
• Localización: XI young researchers meeting on conservation and sustainable use of forest systems / coord. por Elena Hidalgo Rodríguez, Francisco Javier Dorado Reyes, Ainhoa Iñiguez Soto, Diego A. Damián Carrión, Samuel Gato Martín, Guillermo Jové Alcalde, Raúl Arcadio Fernández González, 2017, ISBN 978-84-617-9574-1, pág. 49
• Idioma: inglés
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• Resumen

  • The aim of this work was to evaluate leaves of seven different forest species as baits to isolate Phytophthora from a stream in College Park, MD, USA. Additionally to this, the infection capability of Phytophthora in dried and fresh baits as well as the capability to grow in media containing the fungicide hymexazol were evaluated. The experiment had two sample periods, one during the summer and other during the autumn in 2012. Leaves of seven different species (Pinus strobus, Tsuga canadensis, Ilex opaca, Rhododendron maximum, Quercus rubra, Acer rubrum and Ulmus americana) were selected and collected in the campus of the University of Maryland at College Park, USA. Four experiments trials were performed during the summer and four during the autumn. Four leaves of each species were used as fresh baits and four as dried baits after being dried in an oven (60°C for 24 hours). Once the baits were prepared, it was placed in a mesh bag and submerged in a stream located in the campus and collected after five days. In the laboratory, leaves were washed under tap water to remove any organic matter and posteriorly, in each leaf,seven sections were chosen randomly and were cut and placed in two different types of V8 media: one containing the fungicide hymexazol and other antibiotics and the other with all the antibiotics except hymexazol (10 μg mL−1 pimaricin, 200 μg mL−1 ampicillin, 10 μg mL−1 rifampicin, 25 μg mL−1 pentachloronitrobenzene (PCNB), 50 μg mL−1 nystatin and 50 μg mL−1 hymexazol). Petri dishes were incubated for three days in a temperature of 21°C and after thatthe number of Phytophthora colonies was counted. The different compositions of the media used for isolation did not influence in the number of Phytophthora colonies suggesting their tolerance tothis fungicide. In general, it was observed in both experiment trials that Phytophthora species were able to colonize both fresh and dried baits confirming their behavior as saprophytes in stream ecosystems. The conifers P. strobus L. (White Pine) and T. canadensis L. (Hemlock) were the species which yielded the lower isolation rates during summer and autumn while the broadleaved A. rubrum L. (Red Maple) and U. americana L. (American Elm) were the species whichresulted in the higher isolation rates both for fresh and dried baits and in both sampling periods.