Population Dynamics of Botryosphaeria spp. in Peach Gummosis Cankers. Kerry O. Britton, Graduate Student, Department of Plant Pathology, University of Georgia, Athens 30602. Floyd F. Hendrix, Professor, Department of Plant Pathology, University of Georgia, Athens 30602. Plant Dis. 70:134-136. Accepted for publication 25 July 1985. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/PD-70-134.

Peach twigs naturally infected with the gummosis fungi Botryosphaeria dothidea, B. obtusa, and B. rhodina were sampled at monthly intervals for 2 yr. Fungi were isolated systematically from live twig segments distal to each of 20 cankers on each date to ascertain patterns of twig colonization. Forty percent of the twigs contained all three species. Incidence of Botryosphaeria spp. peaked early in the summer, when all three species were present, and was lowest in the fall. B. dothidea was dominant in the summer. Populations of B. rhodina, though never very large, also increased in the summer. Increases from January to April were due to the presence of B. obtusa, which represented 90% of the population during these months. B. obtusa was isolated every month, but B. dothidea and B. rhodina were not detected in January. Botryosphaeria spp. isolated at the leading edge of colonization distal to the cankers followed a similar seasonal pattern.