Fitopatologia Brasileira (2007) 32, 229-236

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Eugenio Sanfuentes, Acelino C. Alfenas, Luiz A. Maffia and Reginaldo G. Mafia (2007)
Caracterização de isolados de Rhizoctonia spp. e identificação de novos grupos de anastomose em jardim clonal de eucalipto
[Characterization of isolates of Rhizoctonia spp. and identification of new anastomosis groups in eucalyptus clonal nurseries]
Fitopatologia Brasileira 32 (3), 229-236
Abstract: Rhizoctonia spp. cause shoot and leaf blight of eucalyptus in clonal hedges as well as cuttings. Despite the importance of Rhizoctonia spp. to eucalyptus, little is known about their diversity. Thus, we characterized isolates and report new anastomosis groups in a eucalyptus clonal hedge. Isolates obtained at different stages of cutting propagation were characterized according to the number of nuclei in vegetative cells, grouped by morphological characteristics of the colony, anastomosis group, and thiamine auxotrophism. The isolates were also evaluated for virulence on eucalyptus and effect of temperature on their mycelial growth. No correlation between morphological grouping and anastomosis reaction was detected. A wide range of isolates, predominantly binucleate, forms the population of Rhizoctonia spp. present in the soil of clonal hedges, which differed in virulence to eucalyptus. Binucleate and multinucleate isolates had similar growth features at different temperatures, with an optimum growth rate between 25-30 ºC. Isolates of R. solani AG2-2 IIIB and binucleate isolates of Rhizoctonia spp., AG-P and AG-O, as agents of cutting rot, and binucleate isolates AG-A and AG-L in the soil of eucalyptus clonal hedge are reported for the first time.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
(original language: Portuguese)
Full text of article
Database assignments for author(s): Acelino C. Alfenas, Eugenio A. Sanfuentes, Luiz A. Maffia

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution

Pest and/or beneficial records:

Beneficial Pest/Disease/Weed Crop/Product Country Quarant.

Rhizoctonia solani Eucalypt (Eucalyptus) Brazil (south)
Rhizoctonia AG-O Eucalypt (Eucalyptus) Brazil (south)
Rhizoctonia AG-P Eucalypt (Eucalyptus) Brazil (south)