Variability inSeptoria musivain Aggressiveness

Krupinsky, J. M. 1989. Variability in Septoria musiva in aggressiveness. Phytopathology 79:413-416. In growth studies on five different culture media, spore production of North Dakota, South Dakota, and Minnesota. Isolates with high and low Septoria musiva was best on V-8 juice with phytone peptone agar and yeast levels of aggressiveness were selected from the local leaf isolates, the local malt extract agar. A spore concentration of 1 X 106 spores/ml and an canker isolates, and the regional leaf isolates and compared. High and low incubation time of 48 hr were found to promote good symptom develop- levels of aggressiveness were confirmed for the three types of isolates. ment in glasshouse inoculations. Different levels of aggressiveness were Canker isolates were found to be as aggressive as leaf isolates. The local leaf detected for S. musiva in glasshouse inoculations of five Populus clones and local canker isolates were found to be as aggressive as isolates that were with local leaf isolates, local canker isolates, and regional leaf isolates from obtained from a more widespread geographic area.