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Disease Note.

First Report of Alternaria mali on Apples in Yugoslavia. A. Bulajic, Department of Plant Protection, University of Belgrade, 11080 Zemun, Yugoslavia. N. Filajdio, ZENECA Ag Products, Eastern Regional Technical Center, Rt. 1, Box 117, Whitaker, NC 27891; M. Babovic. Department of Plant Protection. University of Belgrade, 11080 Zemun, Yugoslavia; and T. B. Sutton, Department of Plant Pathology, North Carolina State University, Raleigh 27695-7616. Plant Dis. 80:709. Accepted for publication 28 March 1996. Copyright 1996 The American Phytopathological Society. DOI: 10.1094/PD-80-0709B.

A species of Alternaria was isolated from leaf spots on Red Delicious apples (Malus domestica Borkh.) collected from seven locations in Yugoslavia between 1993 and 1995. The leaf spots were circular, tan to brown, 2 to 5 mm in diameter and often bordered by a purple halo. Severely affected leaves abscised; up to 50% defoliation was observed in some orchards. The fungus was identified as A. mali Roberts based on conidial morphology and completion of Koch's postulates. Isolates produced abundant conidia in a dark, carpetlike mycelial mat on potato dextrose agar. Conidia had one to eight septations. The average length and width of conidia of a representative isolate (B0 1/5) of A. mali were 20.9 and 9.2 µm, respectively, which are similar to reported measurements (1). Symptoms similar to those observed in orchards and characteristic of Alternaria blotch were reproduced on leaves of Red Delicious and Mollies Delicious following inoculations in (he laboratory with a conidial suspension. Golden Delicious, Idared, and Jonagold were resistant. A. mali was previously reported from Japan, China, Korea, Zimbabwe, and the United States but this is the first report from Europe.

Reference: (1) N. Filajdic and T. B. Sutton. Plant Dis. 75:1045, 1991.