Pests AND environmental PROBLEMS of High Altitude Landscapes

Jessica Hendryx B.S. in Horticulture Science with a Landscape Design Option ~ Montana State University, Bozeman

Bronze Birch Borer  (Agrillus anxius gory)

Susceptible Plants to the Bronze Birch Borer: Whitebarked Himalayan Birch (Betula jacquemontii); Weeping Birch (Betula pendula)

Less Susceptible Plants: River birch (Betula nigra); Heritage birch (Betula nigra 'Heritage')

Alternative Plant: Common Alder (Alnus glutinosa)

Borers are a common problem on many different types of trees in the landscape. Bronze Birch Borer is a specific insect that attacks Birch. However, here is a list of other common trees/shrubs located in the higher altitudes that are infected by borers, not necessarily the Bronze Birch Borer.

Common Lilac - Syringa vulgaris

Green Ash - Fraxinus penslyvanica

Quaking Aspen - Populus tremuloides

Birch trees are a common high altitude landscape plant. They are frequently planted in dry areas, which is not their natural habitat. Birch trees need  an ample supply of water. Once the water is limited the plants become stressed which then makes them susceptible to borers. The Bronze Birch Borer only attacks trees that are stressed. This can include plants that have root damage, newly transplanted trees, heavily pruned trees, under watered trees, and other various causes.

Placing mulch around the root system will help to conserve moisture around the roots and provide more moderate fluctuations in soil temperatures. Prune individual branches that show the characteristic symptom of borers, the raised areas in the bark, and dispose of before the beetles emerge in the early spring. Do not prune between May and July these wounds may attract egg laying adults. 

To learn more about the Bronze Birch Borer : http://entomology.montana.edu/YardGarden/

or contact:  (wlanier@gemini.oscs.montana.edu)

Montana State University Extension Service 

Designed and researched by Jessica Hendryx - B.S. in Horticulture with a Landscape Design Option
For problems or questions regarding this web contact [martha@montana.edu].
Last updated: April 25, 2002.