First record of Ramularia didymarioides in Australia
I. G. Pascoe A , S. K. de Alwis A , R. Aldaoud A , J. H. Cunnington A C , G. Irvine A and M. J. Priest BA Biosciences Research Division, Department of Primary Industries, Knoxfield, Private Bag 15, Ferntree Gully Delivery Centre, Vic. 3156, Australia.
B New South Wales Department of Primary Industries, Orange Agricultural Institute, Orange, NSW 2800, Australia.
C Corresponding author. Email: james.cunnington@dpi.vic.gov.au
Australasian Plant Disease Notes 3(1) 17-18 https://doi.org/10.1071/DN08007
Submitted: 19 February 2008 Accepted: 5 March 2008 Published: 20 March 2008
Abstract
Ramularia didymarioides was found on potted plants of Silene cv. Rollies Favourite in a nursery in Melbourne. This is the first record of R. didymarioides outside of Europe and central Asia. All affected plants were destroyed.
In November 2007, potted plants of Silene cv. Rollies Favourite were submitted to the DPI Victoria Crop Health Services unit. The plants were 4 months old and had necrotic leaf lesions covering ~10% of the leaf surface (Fig. 1). All of the 200 plants in the grower’s nursery (located in an outer Melbourne suburb) were affected.
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Microscopic examination revealed a species of Ramularia sporulating from the leaf lesions. It was identified as R. didymarioides according to Braun (1998). Conidiophores were erect, filiform, generally flexuous to geniculate, hyaline, simple, mostly 80–125 × 4–5 µm (Fig. 2). Conidia were solitary, 0–2 septate, generally cylindrical, hyaline, roughened, often slightly constricted in the middle or at the septa, mostly 16–27 × 5.5–7.5 µm, with thickened and darkened hila (Fig. 3). A specimen has been deposited in the DPI Victoria Plant Pathology Herbarium as VPRI 41304. A duplicate has been lodged in DAR.
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Ramularia didymarioides occurs in Europe and central Asia (Braun 1998). It has been recorded on the following genera in the Caryophyllaceae: Lychnis, Silene (including Melandrium) and Viscaria (Braun 1998). The Victorian plants were imported from Holland in 2006 as cuttings. No propagation material has been on-sold from the affected plants, which have subsequently been destroyed.
