Cylindrocarpon and Fusarium Root Colonization of Douglas-fir Seedings from British Columbia Reforestation Sites
Poor performance of Douglas-fir (Pseudotsuga menziesit~ plantaffons established in 1987 has occurred in southwestem Briffsh Columbia. Affected sites were planted with oneyear old container stock that exhibited some root die-back in the nursery. A study was initiated in 1991 to assess Cylindrocarpon and Fusarium root infection in planted and naturally regeneraffng (natural) Douglas-fir seedlings from seven affected plantations. Percent of seedlings harboring Cylindrocarpon spp. and percent root colonizaffon was significantly greater for planted seedlings compared to natural seedlings. A significant linear trend in Cylindrocarpon root colonizaffon was observed for planted seedlings with colonizaffon levels being highest for roots closest to the remnants of the root plug and decreasing at distances greater than 10 cm from that region. This trend in Cylindrocarpon colonizaffon was not observed for natural seedlings. Cylindrocarpon destructans var. destructans and C. cylindroides var. cylindroides were the only species isolated from planted and natural conifer seedlings. For most sites, percent of seedlings harboring Fusarium spp. and percent Fusarium root colonizaffon were less than for Cylindrocarpon. Recovery of Fusarium spp. from seedlings and root colonization levels were not significantly different for planted and natural seedlings from all sites.
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