Blue Spruce Update
Since many of you have been inquiring over the past year with the question "What is happening to my Blue Spruce", I thought it fitting to give you all a final answer on the problem.
After sending numerous emails and photographs to Purdue's pesticide lab over the last year, and in their pursuit of a legitimate answer to this overwhelming problem the following is their response in a condensed version.
This information comes directly from Dr. Janna Beckerman at Purdue University.
All Spruce, including Colorado Blue Spruce and it's various cousins are NOT native to this area and can often suffer from stresses such as drought, flooding, salt damage, excessive heat, humidity, insects and even compacted clay soils which we here in this area have plenty to share in case you know of someone in need. They are also susceptible to "needle cast" diseases. Therefore, coming under stress from any or all of the aforementioned makes them even more susceptible to getting one of the various needle cast diseases.
And this is what they are getting and why they are dying according to Purdue.
Needle cast is a fungal disease not caused by an insect.
It starts at the base of an infected tree where the humidity levels are the highest and works its way up until the entire tree becomes defoliated. Spruce trees are Conifers and unlike other trees conifers do not have the ability to replace dropped needles or to push out a second flush of needles. Once they are gone...they are GONE!!
Infected needles may take up to 3 years before showing signs of infection, turning purple to brown and dropping.
|close up of the fruiting bodies on the needles
This fungus produces spores in the spring so if you wish to try and save a tree that is not too infected then this would be the best time for treatment. Fungicides such as Spectro-90, Daconil or other copper based fungicides can help protect new growth and to prevent new infections.
NOTE: It is extremely important to follow the label directions for any pesticide and to wear proper clothing and eye and face protection.
When applying any of these fungicides Timing is of the utmost importance or you are just wasting your time and money. Fungicides should be applied in late Spring when the new needles are 1/2 elongated and again 3-4 weeks later. If wet weather persists during this time you may need to give your tree a third shot in another 3-4 weeks.
It will usually take 2 years of treatment for best results and remember, new needles will not come back out from where they are already missing.
And, even though you do control this problem this year, it will not stop it from happening again in the future. So be vigilant!
Do not apply if it is going to rain and try to limit spraying any fungicide during the heat of the day. Early morning or evening is the best.
Also, prune out the dead or infected branches and rake up any dropped needles that may also be infected. Do any pruning in DRY weather so as not to spread the disease.
It is also a good idea to sterilize your shears between each cut with a mixture of 1 part alcohol :25 parts water. A small spray bottle works well for this.
For future plantings consider planting Norway Spruce which is highly resistant to needle cast. Blue spruce varieties that are also more resistant then the traditional Colorado Blue Spruce are Hoopsi and Fat Albert!
So, now, hopefully you all know the answer to the question "What is happening to my Blue Spruce"