Factors affecting the sporulation of Gloeosporium perennans and Gloeosporium fructigenum in vitro

SUMMARY An ability to spore predictably and plentifully when grown in darkness at a constant temperature, is a highly desirable attribute for any organism used to test antisporulant chemicals in vitro . The extreme variability of isolates, and their rapid loss of vigour in culture, resulted in erratic sporulation by Gloeosporium perennans : although sporulation could be temporarily improved by various means, it remained too variable for assessing the antisporulant activity of chemicals in vitro. G. fructigenum , on the other hand, grew vigorously throughout a long series of transfers, and spored reliably and plentifully when grown under the same conditions.