There is a decline in Colorado Blue Spruce Trees due to insect and disease issues. The issues are impacting growth and aesthetic appeal in many areas. The situation is complicated because trees seem to be happy for a number of years and then they begin to decline as they mature, making them more difficult and costly to remove.

What is the key symptom? Branch dieback. Branch dieback progresses over two to four years of the trees life and creates an unacceptable, diseased, appearance.

What is causing the decline in Blue Spruce Tree appearance? Canker and other diseases and insect problems are the main cause for this species.

Diseases that affect Blue Spruce Tree’s

  1. Needlecasts: Causes the tree to shed needles. What is it? A fungi that infects needles of the current year’s shoots. As the disease progresses, needles die the year following the infection. The result is an outershell of live needles on new shoots, but dead needles on older shoots.
  2. Tip Blights: Cause dieback to new, emerging shoots.
  3. Canker Diseases: Caused by fungi that infect branches or main stem of trees. What are the symptoms? Sunken areas along the stem that may ooze resin. The tree tries to protect itself by producing ridges around the canker infections. As the cankers develop they can interfere with branch functions of transporting water and nutrients. The result of canker disease is death of individual branches.

Insect that affect Blue Spruce Tree’s

  1. Gall Adelgids: A small insect that feed on shoots by sucking plant sap. The damage is mainly aesthetic and the shoots deform and produce galls.
  2. Spruce Spider Mites: The Spruce Spider Mites cause needle discoloration and eventually kills the needles. Spruce Spider Mites can be mistaken for needlecast disease. Not all insecticides will control the mites which are related to spiders.

So, why is this happening to Colorado Blue Spruce Trees? Environmental changed, poor site conditions, and the introduction of new pathogens are to blame. When the trees are being grown in higher humidity fungi has an easier time growing.

Keep in mind, there may be more than one issue affecting a tree at one time. Weak or secondary pathogens are taking shape over time.

Fungicides may be effective in preventing or controlling disease, but only new growth will be protected. For full control, success may take two to three years of yearly application.

Canker diseases will not be effected by fungicides. The best action is to remove branches with the cankers , this will improve appearance and slow the spread of disease.

If insect or mite issues can be resolved with insecticides or miticides, though proper product and timing are critical.

The good news is that not all trees are affected. Diversifying landscape to make trees more resilient to pests and environmental changes is the key. Planting a variety of species whenever possible also helps.

Another piece of good news? The Farm at Green Village is here to help! We want to provide you and your yard the perfect plants to help compliment your landscape. We also want to make sure that you are happy with your purchase, we can lend a helping hand when you come in too!