Canadian Forest Service Publications

The effect of chemical sterilization on the fungus population of soil in relation to root disease of Douglas-fir seedlings. 1965. Bloomberg, W.J. The Forestry Chronicle 41(2): 182-187.

Year: 1965

Issued by: Pacific Forestry Centre

Catalog ID: 24070

Language: English

Availability: PDF (download)

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Nursery beds were treated with methyl bromide, Mylone, Vapam, CIPC, and Simazine before sowing with Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seed. In beds treated by the first three chemicals, the incidence of seedling root disease was 15, 45, and 75% of that in the untreated bed. There was little or no reduction of disease in the Simazine- and CIPC-treated beds. Counts of fungi in soil dilution plates showed that methyl bromide and Mylone caused the greatest reduction in the total fungus population of the soil; the proportion of Trichoderma viride Pers. ex Fr. was larger and that of Penicillium spp. was smaller in soil treated by these chemicals than in soil from other treatments. Vapam caused a moderate reduction in the total population. All treatments reduced the proportion of Fusarium oxysporum Schlect. ex. Fr. in the soil, the fungus principally found to be associated with root disease; however, this proportion did not appear to be correlated with disease incidence.