Root Colonization of Container Western White Pine Seedlings by Fusarium and Cylindrocarpon Species.

摘要

Healthy-appearing container western white pine seedlings were sampled at an Idaho forest nursery eight times during the crop production cycle at monthly intervals for root colonization by potentially-pathogenic Fusarium and Cylindrocarpon spp. in an attempt to better understand epidemiological changes that might occur by these fungi over time. Fusarium spp., especially F. proliferatum, were present at relatively high levels throughout the seedling production cycle. However, Cylindrocarpon (mostly C. destructans) was not detected until seedlings were 4-5 months old. Levels of Cylindrocarpon root colonization remained much less than that of Fusarium spp. Although high levels of Fusarium contaminated seeds prior to sowing, those species most likely to cause disease were only detected at low levels; Cylindrocarpon spp. also contaminated few seeds. During the evaluation period, very low root disease occurred; few culled seedlings and good root plug condition was the standard on the sampled seedling crop.