Susceptibility of Norway spruce seedlings to grey mould in the greenhouse during the first growing season

摘要

The susceptibility of container-grown Norway spruce seedlings [ Picea abies ( L.) Karst.] to grey mould ( Botrytis cinerea Pers.: Fr) during the first growing season after sowing was studied in a production greenhouse and in a small experimental greenhouse in central Finland in 2000. Inoculation with spores was done at seedling ages of 1-6 months. Grey mould caused disease symptoms on the seedlings, i.e. discoloration spots on the needles, on the first and second day after spore inoculation. Inoculation at the seedling ages of 5 and 6 months resulted in the lowest proportion of diseased needles out of the total number of needles, and the number of diseased needles per seedling was also lower compared with inoculations at the ages of 3 and 4 months, with one exception. On uninoculated seedlings, the disease began to appear 3 months after sowing. It was concluded that the seedlings were susceptible up to an age of c. 4 months. During this period, hygiene and unfavourable conditions for the fungus are especially important in controlling disease outbreak.