Forest Health Protection and State Forestry Organizations January 2006

15.7 WEB July 2010 Management Guide for

By John Schwandt Broom US Forest Service arctostaphyli Diet

Primary Host: Topics This causes  Engelmann spruce conspicuous yellow  All spruce are susceptible Damage 1 witches brooms on Life History 1 spruce. Alternate host: Kinnikinnick, uva-ursi Identification 2

Management 2

Other Reading 2 Damage

Field Guide The principal damage from this brooms and their position within the disease is volume and growth loss. crown. Infection and damage may Management Little mortality occurs although also provide infection courts for Guide Index topkill and dead branches are decay fungi. common. Amount of damage depends on the number and size of

Life History

Broom rust alternates between Key Points spruce and kinnikinnick. Spores Broom rust displaying yellow  Principal from the kinnikinnick infect young fungal structures on spruce. spruce needles. The fungus then Photos from Common Tree damage from Diseases of British Columbia. this disease is spreads into the woody tissues of volume and branches and stems where witches'- growth loss. brooms form. The yellow color of these brooms is due to yellow-  Amount of orange fungal structures and spores damage depends on the produced on infected foliage. These number and spores complete the life cycle by size of brooms spreading to kinnikinnick. and their position within the crown.

 Diseased should be eliminated through selective thinning. Alternate host, kinnikinnik. Page 2 Back to menu 15.7

Identification Presence of witches brooms and production of yellow rust pustules on needles. Infected needles are dwarfed and chlorotic, and are often shed annually. Twigs in the brooms are shorter and thicker than normal. At the base of the broom, infected branches and stems are swollen, Infected needles are dwarfed and forming an elongate canker or chlorotic. Photo from Common gall. Brooms and stem swellings Tree Diseases of British Columbia. may be observed after brooms have been shaded out.

Management Considerations

Diseased trees should be eliminated through selective thinning, and infected branches can be pruned from high value trees, such as those around dwellings and in concentrated recreation sites.

Other Reading Forest Health Protection and State Baranyay J. A. and Ziller W. G. 1972. Forestry Organizations Broom Rusts of Conifers in British Columbia. Forestry Canada, Forest Insect Assistance on State Assistance on and Disease Survey, Forest Pest Leaflet And Private Lands Federal Lands No. 48 6p. Montana: (406) 542-4300 US Forest Service Region One Idaho: (208) 769-1525 Missoula: (406) 329-3605 Allen, E.A., D.J. Morrison, and G.W. Coeur d’Alene: (208) 765- Wallis. 1996. Common Tree Diseases of Utah: (801) 538-5211 7342 British Columbia. Natural Resources Nevada: (775) 684-2513 US Forest Service Canada, Canadian Forest Service. Region Four Wyoming: (307) 777-5659 Ogden: (801) 476-9720 Ziller, W. G.1974. The tree rusts of western N. Dakota: (701) 228-5422 Boise: (208) 373-4227 Canada. Canadian Forestry Service, Dept. of the Environment, Victoria, B.C. Publication No. 1329.

Photos from Canadian Forestry Services http://forestry-dev.org/diseases/ctd/Group/Rust/ rust1_e.html

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