01657naa a2200169 a 450000100080000000500110000800800410001910000170006024501160007726000090019352011690020265000110137165000110138265000120139365000100140577300720141518326752011-08-16       1978    bl ---       0--  u    #d1 aCLARK, R. V.  aDistribution and severity of root and leaf diseases and cereal leaf beetle damage of barley in western Ontario.  c1978  aBarley fields in western Ontario were surveyed for incidence of root rot and foliage pests from 1972 to 1975. Estimates of the effect of common root rot caused by Cochliobolus sativus on barley yields using discoloration of the subcrown internode as a measure of the amount of disease indicated that 4.3 and 0.8% of the crop was lost in 1972 and 1974, respectively. In 1973, an 8.3% increase in yield occurred in plants discolored by root rot. Because of the wide variation in yields and lack of adequate subcrown internodes it would appear that this method of determining root rot damage to barley may not be usable in Ontario. An early season survey in 1975 showed that pathogenic Pythium spp. were present in soils but there was no definite evidence of root rot damage from these species. Spot blotch (C. sativus) was the most severe and prevalent foliage disease of barley from 1973 to 1975. Scald (Rhynchosporium secalis), leaf rust (Puccinii horde,) and powdery mildew (Erysiphe graminis) occurred irregularly in trace amounts. Damage to the foliage caused by the cereal leaf beetle (Oulema melanopus) was minor and decreased each year of the foliage survey.  aCanada  aCereal  aDoença  aPraga  tCanadian Plant Disease Survey, Ottawagv. 58, n. 2, p. 33-38, 1978.