Untersuchungen zur Biologie,Morphologie und Verbreitung von Herpotrichia parasitica (Hartig) E. Rostrup (vormals Trichosphaeria parasitica Hartig)

Studies on the biology, morphology and spread of Herpotrichia parasitica (Hartig) E. Rostrup (formerly Trichosphaeria parasitica Hartig). Part II: Method of infection, hosts and pure culture. H. parasitica (Hartig) E. Rostrup (conidial stage Pyrenocbacta parasitica Preyer et van der Aa) overwinters by means of both types of fruit bodies on the needles of hosts but also by means of mycelium which grows along the under sides of shoots during the growing season, reaches the buds and penetrates under the outer bud scales. Spread of the fungus is thus independent of spores. As well as Abies alba, other silver firs are attacked. Contact infection with mycelium on Picea sitchensis was also observed. Studies with pycnospores showed that germination on needles of host species varied with humidity. In culture the fungus grew best on 2 % malt agar, pH 6 at 21°C.