Abstract:
Using soil bioassays and isolations from field plants to survey soil-borne fungi causing sugar beet diseases in commercial fields in southern Sweden, damping-off pathogens, Aphanomyces cochlioides, Pythium sp. and Rhizoctonia solani,were the main pathogens found. Of the 1260 plants sampled from 28 fields, 8.5% were infected by these pathogens. Of 1120 seedlings grown in greenhouses in soil from these fields, 6.4% were infected by A. cochlioides and 10.7% were infected by Pythium sp. P. sylvaticum (for first time reported as a pathogen of sugar beet in Sweden). P. ultimum and A. cochlioides were also frequently isolated and were pathogenic in all tests. R. solani AG-2-1was occasionally isolated and Fusarium sp. were frequently isolated, but were in most cases not pathogenic to test plants. Field soil sampling, seedling sampling, isolations and symptom assessments all indicated that Pythium sp. was predominantly the cause of pre-emergence damping-off, but diseased seedlings in later stages were infected mainly by A. cochlioides. In general, historically high-yielding fields in the area had less seedling diseases and damping-off problems than average yielding fields.
Subscribe Today 
