Studies on the Biological Characteristics of Pathogen, Diplodia pinea of Slash pine Dieback

The pathogenic fungus causing dieback of slash pine is Diplodia pinea(Desm.)Kickx.In full light and at 25～31℃,the fungus grows best on PDA medium,and forms its fructification early. Its conidia germinate best on l0% needle in fusion of Pinus elliottrii and P.tablaeformis. Its germination percentage after 6 hours reaches over 90%. Optimum temperature for conidial germination is between 25℃ to 30℃,and pH 6～7 the most favorable.Germination percentage in water drops is higher than that under saturated moisture condition,Light has no obvious influence on conidial germinating.