Growth, Sporulation, and Mucilage Production by Ceratocystis fagacearum at High Temperatures. F. H. Tainter, Professor, Department of Forestry, Clemson University, Clemson, SC 29634-1003. Plant Dis. 70:339-342. Accepted for publication 14 October 1985. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/PD-70-339.

Ceratocystis fagacearum was grown at high temperatures and observed for growth and morphology. Germination of conidia of a South Carolina isolate was significantly greater at 32 than at 24 or 28 C, whereas linear growth rate of germ tubes at 32 C was less than 50% of the growth rate at 24 and 28 C. Scanning electron microscopy revealed profuse mucilage and conidia produced in colonies of South Carolina and Texas isolates at 24 C, whereas at 28 C, there were decreased mucilage and fewer conidia. At 32 C, there was little hyphal growth, few conidia, and virtually no mucilage. Similar behavior of South Carolina and Texas isolates within oak trees at high temperatures may help explain the slow progress or arrested symptoms of oak wilt caused by these isolates in nature.