Delphinella shoot blight and Grovesiella canker on Abies lasiocarpa in western USA

ABSTRACT

The impact of Delphinella shoot blight (Delphinella abietis) and Grovesiella canker (Grovesiella abieticola) on subalpine (Abies lasiocarpa) and corkbark fir (A. lasiocarpa var. arizonica) in a provenance trial in Idaho (ID) was evaluated in 2013. Both pathogens were previously reported from North America on fir species. D. abietis had been found on subalpine fir in USA, but not in ID, and G. abieticola on grand fir (Abies grandis) in ID, but not on subalpine or corkbark fir. D. abietis kills current-year needles and in severe cases buds and shoots, and G. abieticola results in dead shoots and branches and can eventually kill whole trees. Significant differences between provenances in susceptibility to D. abietis and G. abieticola were observed in the provenance trial in ID. In general, subalpine fir was more susceptible to both diseases than corkbark fir. In 2013, D. abietis was also found on subalpine fir in the Puget Sound area of Washington State and G. abieticola was seen on white fir (Abies concolor), but neither disease was detected in native stands of subalpine fir in Washington State. Morphological features of both fungi were described from samples collected in the provenance trial in ID in May 2016.

KEYWORDS:

• Delphinella abietis
• Grovesiella abieticola
• subalpine fir
• corkbark fir
• Abies lasiocarpa var. arizonica
• provenance trial
• Idaho

Acknowledgments

The authors want to thank Tom and Carolyn Leege, members of the Inland Empire Christmas Tree Association (IECTA) and Mike Bauer, Idaho Cooperative Extension for opening the provenance trial at Sandpoint to us.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The field surveys in 2013 and 2016 were part of the project “Fjelledelgran – norsk juletresatsing truet av sopp?” [Subalpine fir – Norwegian Christmas tree production threatened by fungal infection?] funded by the Research Council of Norway (225365) and supported by Washington State University.