Phomopsis subordinariaand associated stalk disease in natural populations ofPlantago lanceolate

摘要

Natural populations ofPlantago lanceolataL. can be infected by the fungusPhomopsis subordinaria(Desm.) Trav., which causes a stalk disease. Inoculation experiments revealed that the fungus needs a wound to enter the plant tissue. Symptoms of the disease in the field and from inoculation experiments in the greenhouse are described and the taxonomic position of the fungus is discussed. The pathogen could not be isolated from other plant species in heavily infectedPl.lanceolatapopulations and can be regarded as specialized onPl.lanceolata. Other species of the genusPlantagodiffered considerably in their susceptibility to the disease. Comparison ofPl.lanceolatagenotypes indicated that there is variation in susceptibility among host genotypes. Because the disease may reduce the production of viable seeds, the possibility of natural selection for resistance in the host is considered.