Surveys of stem base diseases and fusarium ear diseases in winter wheat in England, Wales and Scotland, 1989–1990

Abstract

SummaryAn investigation into the incidence of stem base diseases and the pathogens associated with them was undertaken on winter wheat samples collected at growth stages 31 and 73–75 in 1989 and 1990. Symptoms at growth stage 31 were classified into 10 different types based on visual characteristics. Although Pseudocercosporella herpotrichoides was associated mainly with eyespot lesions and Rhizoctonia spp. with sharp eyespot lesions, a significant number of isolates of each pathogen were taken from lesions classified as fusarium. Different types of fusarium lesion on stem bases at both growth stages were not associated with any one particular Fusarium or Microdochium species. 98% of P. herpotrichoides isolates obtained from eyespot lesions at growth stage 31 in 1989, and 87% of those obtained in 1990 were identified as the sub‐species P. herpotrichoides var. acuformis, Microdochium nivale was more common than any of the Fusarium species at both growth stages, and was particularly prevalent in samples from Scotland at the earlier growth stage in 1989. Isolations from the top internodes at growth stage 73–75 indicated that systemic infection by Fusarium species, although present in some stems, was of little importance. Fusarium ear blight affected 0.4% of ears in 1989 and 0.5% in 1990. Glume spot lesions on the ears in 1990 were predominantly associated with Fusarium poae.