The Distribution of the Mycelial Types of Gloeodes pomigena on Apples in North Carolina and Their Relationship to Environmental Conditions. ABBEY L. SUTTON, Former Graduate Research Assistant, Department of Plant Pathology, North Carolina State University, Raleigh 27695-7616. T. B. SUTTON, Professor, Department of Plant Pathology, North Carolina State University, Raleigh 27695-7616. Plant Dis. 78:668-673. Accepted for publication 21 March 1994. Copyright 1994 The American Phytopathological Society. DOI: 10.1094/PD-78-0668.

The distribution of the four mycelial types of Gloeodes pomigena was determined by monitoring their incidence and severity in eight locations throughout North Carolina in 1986 and 1987. Temperature, rainfall, and relative humidity were monitored at four sites in 1986 and seven sites in 1987 throughout the growing seasons. The incidence of sooty blotch approached 100% at all locations by the end of each growing season. Severity of the disease was highest at locations with cooler temperatures and longer periods of dew (western Mountains) or higher humidities (eastern Coastal Plain). The punctate mycelial type was most common overall and was most prevalent in areas where disease severity was greatest. The incidence and severity of the punctate type increased with increasing hours of high relative humidity; severity decreased with increasing temperature. The incidence and severity of the ramose mycelial type increased with increasing temperature and increasing amount of rainfall. This type was most abundant in the Coastal Plain region. There were no significant correlations between any environmental factors and the fuliginous mycelial type. The incidence and severity of the rimate type was correlated positively, although weakly, to measures of relative humidity.