FUNGI COLONIZING SCOTS-PINE CONE SCALES AND SEEDS AND THEIR PATHOGENICITY

Fungi were isolated from the cone scales and seeds of Scots pine using plating an male-extract agar and/or the standard blotter method in a Jacobsen's apparatus. Alternaria alternata, Epicoccum purpurascens and Ulocladium atrum were isolated from damping-off seedlings germinating on agar or filter paper, but, in pathogenicity tests with pear-sand ( 1:3) growth substrate, they were not pathogenic. All the Fusarium spec ies isolated were pathogenic in growth substrate. Some F. avenaceum co lonies formed no aerial hyphae and they proved to be a mixed culture o f the fungus, a fluorescent Pseudomonas sp., and a gram-negative bacte rium. The bacterial associates appeared to increase the pathogenicity of F. avenaceum. All the micro-organisms tested were more pathogenic i n sterilized than in unsterilized pear-sand substrate.