Influence of Temperature and Moisture on Germination of Ascospores and Conidia of Botryosphaeria dothidea. T. B. Sutton, Department of Plant Pathology, North Carolina State University, Raleigh 27695-7616. L. F. Arauz, Department of Plant Pathology, North Carolina State University, Raleigh 27695-7616. Plant Dis. 75:1146-1149. Accepted for publication 22 April 1991. Copyright 1991 The American Phytopathological Society. DOI: 10.1094/PD-75-1146.

Predicted optimum temperatures for germination of conidia of isolates 1, 2, and 3 of Botryosphaeria dothidea in free water were 26.7, 27.8, and 29.5 C. Conidia of isolates 1 and 2 germinated at 8 C after 24 hr but none from isolate 3 germinated. Conidia of isolate 1 incubated at 95–100% relative humidity (RH) germinated after 12 hr; the percent germination declined with RH. Few conidia of isolates 2 or 3 germinated in the absence of free water. The predicted optimum temperature for ascospore germination was 24.6 C. Ascospores germinated over a wider range of RH than did conidia (92–100%); percent germination declined with RH. Ascospore germ tube length declined with RH. Air drying for approximately 20 min significantly reduced the viability of conidia. Conidia from isolates 2 and 3 were more sensitive to drying than isolate 1.