First Report of Stemphylium botryosum Causing Stemphylium Leaf Spot of Asparagus in Greece. K. Elena, Benaki Phytopathological Institute, 145 61 Kifissia-Athens, Greece and National Agricultural Research Fundation, Athens, Greece. Plant Dis. 80:342. Accepted for publication 24 January 1996. Copyright 1996 The American Phytopathological Society. DOI: 10.1094/PD-80-0342D.
The disease "summer burning" incited by Stemphylium sp. was first observed on asparagus (Asparagus officinalis L.) crops in northern Greece during the summer of 1992. In August, September, and October of 1995 a severe drop of cladophylls (small needlelike branches) again was observed in many production fields after periods of heavy rainfall. In all fields debris from the previous summer's fern growth was lying on the soil surface. Numerous brown lesions with dark purple margins were present on the main stems, branches and cladophylls of the affected ferns. Stemphylium spores were observed on the lesions. Diseased green ferns were surface disinfested in sodium hypochlorite and the lesions were excised and plated on potato dextrose agar. The pathogen was isolated from lesions and identified as Stemphylium botryosum Wallr., based on the following characteristics: conidia variously subspherical, oblong or broadly ovoid 19 to 29 µm x14 to 23 µm and with a length/width ratio of 1.2:1.4 (1,2). Asparagus inoculated in the greenhouse without wounding and maintained at 20°C and 70% humidity developed symptoms similar to those observed in the field and the fungus was reisolated from affected tissues. There were no symptoms on asparagus spears from plants with symptomatic ferns because spears are always harvested before emergence from the planting beds in Greece. This is the first report of Stemlhylium botryosum causing the disease "summer burning" of asparagus in Greece.References: (I) P. G. Falloon et al Phytopathology 77:407, 1987. (2) E. Simmons, Mycologia 61:l, 1969.