Current issue: 57(1)
Under compilation: 57(2)
The purpose of this article was to collate the literature on fungal diseases that occur on seedlings in forest nurseries. It describes the symptoms of the diseases, the infection pattern of each fungus and the possibilities of controlling the diseases. As background a short introduction is given on forests and nursery practices in Finland.
Based on a survey of world literature it is concluded that 1) the better -researched epidemic forest pathosystems are caused by anthropogenic factors, 2) the systems most likely have a polygenic background, and 3) resistance breeding should maintain polygenic resistance with restrictive incorporation of oligogenic resistance. Corresponding objectives are valid in breeding programs of presently balanced pathosystems, which may turn epidemic if man causes changes in the gene pool and alters critical environmental conditions.
The PDF includes an abstract in English.
Department of plant pathology of University of Helsinki conducted studies in the surrounding forests of Viikki test farm and on the Hyytiälä forest training station to find about occurrence and spore production of pine needle rust.
The damages have been minor. Most often the infection did not cause yellowing of the needles, only individual needles might have dried up. There were no dead young trees.
The spore production was strongest at the more fertile sites, with abundant occurrence of cow-wheat (Melanpyrum spp.). The infection caused more harm on the cow-wheat than on the pines. In many cases the foliage died prematurely. Melanpyrum spp. were more strongly infected on sites with more light. However, there was no difference found with the fertility of the site.
The PDF contains a summary in Finnish.