First Report of Anthracnose Fruit Rot of Strawberry Caused by Colletotrichum acutatum in Montenegro

Strawberries (Fragaria × ananassa) in Montenegro have become an increasingly important economic crop in recent years. During May 2011, severe fruit damage in strawberry cv. Clery was observed in two fields in the Podgorica region. Fruit symptoms were typical for strawberry anthracnose: sunken, dark brown to black circular lesions appeared on maturing fruits. However, no stem, crown, or foliar symptoms were observed. Under wet conditions, orange masses of conidia were produced in acervuli in the center of lesions. Conidia were hyaline, aseptate, cylindrical, with pointed ends, measuring 9.8 to 17.2 (mean 14.3) × 2.5 to 6.1 (mean 4.4) μm. Colonies on potato dextrose agar (PDA) were initially white, then turned gray as conidia formed in orange to salmon pink masses around the center of the culture. Setae or an ascigerous stage were never observed in culture or on the host. Koch's postulates were fulfilled by inoculating ripe and unripe asymptomatic fruits (20 of each, removed from strawberry plants cv. Clery) with the isolated fungus. Fruits were sprayinoculated (10⁶ conidia/ml). An equal number of noninoculated fruits were used as a control. After incubation time of 2 to 3 days at 25°C in a moist chamber, symptoms appeared on inoculated ripe fruits. On unripe fruits, the lesions developed only 3 to 4 days after the inoculation. No symptoms were found on control fruits. The fungus was reisolated from fruits, after which typical morphological characteristics developed in culture as described above. On the basis of the symptoms, the morphological and cultural characteristics of the fungus, and the pathogenicity test, the disease was identified as strawberry anthracnose caused by Colletotrichum acutatum, which is in accordance with previous reports (1,2,3,4). The isolate was submitted to the Centraalbureau voor Schimmelcultures in the Netherlands (CBS 131813). The internal transcribed spacer (ITS) region of the fungal DNA was amplified with ITS1F and ITS4 primers, sequenced, and submitted to NCBI GenBank (Accession No. JQ424934). BLASTn searches of GenBank using the ITS sequence revealed 99% similarity with database sequences of C. acutatum. Since the pathogen was found in the main Montenegrin strawberry production area, it poses a threat to strawberry production in Montenegro. To our knowledge, this is the first report of anthracnose fruit rot of strawberry in Montenegro.References: (1) S. G. Bobev et al. Plant Dis. 86:1178, 2002. (2) F. M. Dai et al. Plant Dis. 90:1460, 2006. (3) U. Nilsson et al. Plant Dis. 89:1242, 2005. (4) A. Stensvand et al. Plant Dis. 85:558, 2001.