Previous View
 
APSnet Home
 
Plant Disease Home


Disease Note

Occurrence of Aphanomyces euteiches f. sp. phaseoli on Beans in New York State. H. R. Dillard, Department of Plant Pathology, Cornell University, New York State Agricultural Experiment Station, Geneva 14456. G. S. Abawi, Department of Plant Pathology, Cornell University, New York State Agricultural Experiment Station, Geneva 14456. Plant Dis. 72:912. Accepted for publication 22 July 1988. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/PD-72-0912C.

Root and hypocotyl rot of beans (Phaseolus vulgaris L.) incited by Aphanomyces euteiches Drechs. f. sp. phaseoli was observed for the first time in commercial fields in the western area of New York State during 1986. The disease was first recorded on beans in the United States in 1982 (1). The pathogen was isolated by plating washed root and hypocotyl segments of symptomatic plants obtained from two fields on Aphanomyces-selective medium (2) at 25 C. Roots of 8- to IO-day-old bean seedlings (cv. Bush Blue Lake 47) were dipped in mycelial fragment or zoospore inocula of this pathogen and transplanted into steam-pasteurized soil. The fungus caused severe root rot symptoms and significantly reduced dry weight ofthe bean seedlings in the greenhouse. No symptoms were observed on pea (Pisum sativum L. 'Knight') or table beets (Beta vulgaris L. 'Ruby Queen'), confirming the identity of the pathogen as A. e. f. sp. phaseoli. Seed and soil treatments using fenaminosulf, but not metalaxyl, were highly effective in controlling the disease.

References: (1) W. F. Pfenderand D. J. Hagedorn. Phytopathology 72:306,1982. (2) W. F. Pfender et al. Plant Dis. 68:845, 1984.