Concolor Mystery

Asked December 5, 2019, 3:48 PM EST

I am responding to a request from John S. who requested photos of affected limbs

Denver County Colorado

1 Response

Cytospora is a fungus which can kill limbs on fir trees. In many cases you can observe cankering on affected limbs; I did not observe any such cankers in your photos, but it may be worth doing a little bit of further investigations.

The following links provide some pictures and more information on this pathogen:

While I don't believe cold injury to be the cause of these dead limbs, I want to provide you with some information on cold injury because it is the season: https://www.canr.msu.edu/uploads/files/AABI/Assessing_winter_injury_in_conifers_2015.pdf

Winter Browning: https://planttalk.colostate.edu/topics/weeds-cultural-problems/2114-winter-browning-evergreens/

Winter water can help alleviate drought related problems: https://extension.colostate.edu/topic-areas/yard-garden/fall-and-winter-watering-7-211/