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ARS Home » Midwest Area » East Lansing, Michigan » Sugarbeet and Bean Research » Research » Publications at this Location » Publication #112380
Title: A SURVEY OF PYTHIUM SEEDLING DISEASE IN MICHIGAN SUGARBEET FIELDS-1999

Author
item JOHNSON, DAVID - MICHIGAN ST UNIVERSITY
item Halloin, John

Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 5/24/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Michigan sugarbeet growers have expressed concern over poor stand establishment in recent years; seedling disease caused by a complex of pathogens contributes to this problem. Pythium spp. are the pathogens most frequently isolated from diseased seedlings in MI. In 1999 we surveyed for Pythium spp. in fields exhibiting seedling disease problems. While P. ultimum was most commonly isolated, other isolates included: P. aphanidermatum, P. irregulare, and several tentatively identified as P. dissotocum. There was a close association between pathogenicity and tolerance to metalaxyl (>50% reduction in colony growth rate by 1 ug/ml metalaxyl), a fungicide applied to all commercial sugarbeet seed to control Pythium disease. The presence of pathogenic Pythium spp. with metalaxyl tolerance indicates the need for improved control measures for this pathogen.