Mycorrhizal fungi as a biological control agent in pine forests threatened by root rot (Heterobasidion annosum (Fr.) Bref.)

In the paper some results of studies on ability of mycorrhizal fungi to protect Scots pine seedlings against Heterobasidion annosum are presented. Mycological observations on the occurrence of higher fungi in pine forests injured by Heterobasidion root rot revealed relatively less abundant fructification of the fungi on areas of still active disease centres in comparison with high frequency of sporocarps found on old disease centres. Results of comparative studies on the antagonism to H. annosum showed highly significant variation among mycorrhizal fungi in ability to influence the pathogen growth in plate test and in the rhizosphere of host plants. The natural diversity of the fungi in restricting the pathogen growth suggests the possibility of selection the best pathogen/antagonist combination for various sets of environmental conditions.