| dc.description |
An evaluation was conducted at the USDA Forest Service Nursery, Coeur d'Alene,
Idaho, to quantify the occurrence of diseases in the spring 1984 crop of
containerized Engelmann spruce seedlings. The crop included 19 separate
seedlots from seven National Forests in the Northern Region. An overall
production rate of 94.5 percent was achieved for the crop (5.5 percent of the
crop was lost to diseases or other mortality factors). Dead or diseased
seedlings accounted for only 0.7 percent of the total losses, whereas empty
cells accounted for the remaining 4.8 percent. Major disease organisms
included Sirococcus strobilinus, Fusarium oxysporum, F. avenaceum, F. solani,
F. tricinctum, Cylindrocarpon tenue, Phoma herbarum, P. fimeti, and Botrytis
cinerep. Sirococcus caused disease in 18 of the 19 seedlots and was usually
encountered about 11 weeks after sowing. Fusarium diseases occurred with
greatest frequency shortly after germinate emergence. |
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