Canadian Forest Service Publications

The occurrence and assessment of fungal parasites as potential biological control agents of western hemlock dwarf mistletoe. 1999. Shamoun, S.F. Phytopathology 89(6) Supplement: S71.

Year: 1999

Issued by: Pacific Forestry Centre

Catalog ID: 5248

Language: English

Availability: Not available through the CFS (click for more information).

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WESTERN HEMLOCK DWArF MISTLETOE(WHDM) (ARCEUTHOBIUM TSUGENSE SUBSP. TSUGENSE) IS A PARASITIC PLANT OF SEVERAL CONIFERS AND CAUSES SUBSTANTIAL REDUCTION IN TREE GROWTH, LOWERING WOOD QUALITY AND CAUSING MORTALITY. A FIELD SURVEY WAS CONDUCTED IN THE COASTAL SOUTHERN REGION OF BRITISH COLUMBIA TO collect and identify fungal parasites associated with WHDM. A total of 223 isolates of more than 20 ascomycetes and fungi imperfecti were isolated and identified. Two new fungal records were discovered, colletotrichum gloeosporioides on whdm on western hemlock, and a new species of nectria on swollen branches infected by the shore pine pathotype of whdm. Assessment of the biological control potential of fungi collected is under way. Hemlock seedlings, aged 2 yr. and 5 yr., were infected with whdm seeds under greenhouse conditions. After 6 months, swelling were detected on branches and aerial mistletoe shoots wee observed on seedlings at 18 and 6 months respectively. Two fungi, C. gloeosporioides and N. neomacrospora were applied singly and in combination to WHdm clusters. The results and their applications under partial cutting systems will be discussed.