First report of Macrophomina phaseolina causing strawberry crown and root rot in northwestern Argentina.

The winter strawberry (Fragaria ananassa Duch.) industry in subtropical regions is characterized by early-season fruit production, a time when crop value is the highest. This is the case of the northwestern province of Tucuman (27°S), Argentina's largest winter strawberry growing area (2). Collapsed and dying strawberry plants of cv. Camarosa were observed in commercial farms in Tucuman in September 2007 with an incidence of 16%. Crowns and roots of affected plants revealed dark, external and internal browning tissue with several dark, oblong, subepidermal sclerotia. Pieces of necrotic crowns and roots disinfested with 0.6% chloride for 30 s were placed on potato dextrose agar (PDA). After 4 days of incubation at 25°C with constant fluorescent lighting, dark cultures with numerous, dark, oblong sclerotia immersed in the isolation medium were observed. Sclerotia size ranged from 70 to 120 μm in 7-day-old cultures. The isolated fungus was identified as Macrophomina phaseolina (3). Ostiolate pycnidia bearing...