Good afternoon. I've noticed that our Blue Spruce is losing its luster over the past 2 years or so. The branches look like they're thinning out and turning brown - especially towards the bottom. Please let me know if you have a suggestion on how to treat this problem so we can get our tree looking healthy again.
Blue spruce can be susceptible to Cytospora canker and Rhizosphaeria needlecast, fungal diseases. Blue spruce, in general, are not really well suited for our area as they are native to climates further to the north. Cytospora canker occurs on trees stressed by drought or other site conditions. There is not much you can do other than water during dry periods. Make sure mulch is no thicker than several inches and keep away from the base of the trunk. Prune dead plant material during dry weather. http://extension.umd.edu/hgic/cytospora-canker-spruce
Rhizosphaeria needle cast disease. The infection period is long - spring through midsummer. The needles are affected in the fall and needle drop occurs in the spring. Pruning out severely infected branches is the best control method on branches that show sparse growth. Spraying large trees with fungicides can be complicated - getting good coverage, timing, etc. and not recommended. For more information see the link on our website http://extension.umd.edu/hgic/evergreen-needle-cast-diseases-trees-and-shrubs mh