Question
QUESTION: Hi, I would really appreciate some feedback to help us decide what to do.  We have a whopping 22 (30-40 yr old) Colo. Blue Spruce trees on our property.  2 years ago, we noticed severe needle drop on several of the trees, as well as some rapid browning of a few branches after several years of drought. In addition, we had some virus in a few of the trees that made purple needs. After several consults, we hired a reputable tree service (and let me emphasize, not the cheapest) come out and do heavy pruning throughout our lot at the end of march last yr. and followed a treatment plan from march thru oct. of spraying all the trees, fertilizing by ground injection, etc. ($6,000) We are saddened to see that several of the trees are showing signs of severe stress and probably dying, even after all of this treatment (its weird, because you can tell by the bark turning this greyish tint, and of course the continous die out of branches over this winter.)  The tree service is of course, recommending that we cut down one maybe two of the trees, but continue with another year of treatment (spraying,fertilizing, and a few injections on the sickest trees) at $3,000...and we would have to water alot throughout the season.  We are concerned for two reasons, one, this yr. we have had a severe economical hit with our finances with a job loss, and two, does a second treatment really help or are we just pouring good money down the drain?  We are on wells out here, so watering regularly is not terribly realistic (we would be watering these trees daily, as there are so many, our pump would go constantly.)  I posed this same question to the tree service and they said we could try to water all trees regularly and feed ourselves but it would be a crapshoot, and I am not sure about how we would manage that.  $3,000 is alot considering our current financial status, but, I know the value the trees also add to our property. What would you honestly recommend, and if we can do this ourselves until we get back on our feet, what type of fertilization would you recommend. As for the watering, what is the best way to water 30 year old trees??
Put a hose right at the base of the tree??? We live in the NW suburbs of Chicago, and have had a tremendously snowy winter, with some exceptional cold temps.  Who knows what summer will bring....
Thanks for any light you can shed on our issue.

ANSWER: The disease, Rhizosphaera needle cast, frequently infects Colorado blue spruce. Rhizosphaera is a fungal disease that infects the current year's needles. These needles turn purple to brown and fall from the tree prematurely, leaving the inner portion of the branch bare. As the disease progresses, severely infected branches die, leaving the tree with a hollow or thin appearance. The disease starts near the base of the tree where humidity levels are the highest, and continues upward. As the disease continues, trees lose their value as a screen or privacy fence.

Thee are fungicides that can be used but a tree this size would be difficult to treat. Colorado Blue Spruce in Chicago is out side its natural range and they will gave more problems than trees native to the area. In general, stress makes trees more susceptible to disease. We can minimize stress to trees by choosing an appropriate tree for the site, buying high-quality planting stock, planting it properly with proper spacing, giving it a three-inch-deep layer of mulch over the rootzone, and watering it during especially dry periods. This "preventative maintenance" is the best way to manage tree problems.
I would lay off the fertilizer and pruning and just water. First rake up the infected needles that have fallen and move them off the site. This will cut down on the amount of spores that will reinfect the new trees. Mulch around the trees with 3 inches deep of organic mulch out to about 5-6 feet around the trees making sure it is not pilled up on the trunk. Water when it does not rain once a week with 1 inch of water per tree. Place a pan under the tree and turn the sprinkler on and when the pan has 1 inch of water in it stop. This will deep water the tree and cause the roots to grow deeper. daily watering tends to make the roots grow shallow and then when a drought comes the roots can not get water that is deeper in the soil.
The stress I think is the main problem setting up the needle cast disease so watering deep should solve that.

I would suggest you also contact the Illinois Forestry Extension Service and ask them if they could come and look at your problem. If they are not able to come out they can give you good sound advice free. Here is the contact there and their web site.

Philip L. Nixon, Ph.D.
Extension Entomologist
S408 Turner Hall, (MC047)
1102 South Goodwin Ave.
Urbana, Illinois 61801
Email: [email protected]

http://web.extension.uiuc.edu/forestry/forest_health.html





---------- FOLLOW-UP ----------

QUESTION: Thank you for all the good information and I will make that call to the forestry dept.  I do have one additional question re: pruning.  You mentioned in your response to not fertilize or prune.  Do you mean we "should"
leave the 12 or so assorted branches that appear to have died over the winter (brown/orange needles or barren) still on the tree???  Or should we prune those out, sterlizing between cuts, and then do not prune anymore from that point on?  I am not sure I understand whether dead branches add to the ill health of the tree's or not or if they are just unsightly.  
Thanks so much.
Cathie

Answer
It is your choice on whether to cut the dead branches or not. They will not add to or decrease the health of the tree. But I would not prune any more green branches off. The fertilizer will add to the need for water and I would hold off on fertilizing until you get the tree back to normal.
If the cost of cutting the dead limbs is too high you can wait and over time the limbs will shed off by themselves. The tree may look ragged with the dead limbs though.