|
Disease Note. First Report of Crown Rot (Phytophthora cactorum) of Strawberry in Eastern North America. W. F. Wilcox, Department of Plant Pathology, New York State Agricultural Experiment Station, Cornell University, Geneva 14456. . Plant Dis. 73:183. Accepted for publication 30 November 1988. Copyright 1989 The American Phytopathological Society. DOI: 10.1094/PD-73-0183E. Wilting and dying strawberry (Fragaria × ananassa Duch. 'Raritan') plants with no symptoms of red stele, yet with variable levels of root necrosis and red-brown, basipetally advancing lesions within the crown, were observed in two fields in Suffolk County (Long Island), New York. Affected plants in one field (third-year fruiting) were concentrated in a low, wet area, whereas those in a newly planted field were distributed randomly. Isolations from necrotic crown tissue onto P5ARP or P5ARPH media (1) consistently yielded Phytophthora cactorum (Leb. & Cohn) Schroet. An isolate from each field caused crown rot, wilt, and collapse of greenhouse-propagated strawberry plants grown for 8 wk at 25 C in pasteurized soil infested with colonized vermiculite inoculum (2%, v/v) and flooded for 48-hr periods at 2-wk intervals. In contrast, two isolates of P. cactorum from apple crowns and one each from a raspberry root and crown caused no disease, supporting the contention that crown rot of strawberry is caused by a distinct pathotype of P. cactorum (2). This is the first report to confirm the occurrence of crown rot (vascular collapse) of strawberry in eastern North America. |