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The Joy of Gardening

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Browning on Colorado Blue Spruce 'Fat Albert'

I have a Colorado Blue Spruce 'Fat Albert'. I noticed last year that it wasn't looking good. I was out today looking at it, only to find that the needles in the whole heart of the tree seem to be turning black and falling off. Is there anything I can do to save it?

Your description leads me to believe that it is Rhizosphaera needle cast, which is a fungal disease. Rhizosphaera needle cast causes older needles in the centers of trees to turn brown or purple, and then fall off. The new needles at the tips of branches remain green and unaffected. This disease spreads by splashing water and it overwinters in both live and dead needles. Needle cast will often start in the lower branches and move upwards though the tree. Cultural control options include increasing air circulation around trees, (spacing, selective pruning), selecting a full sun location, avoiding sprinklers wetting needles and avoiding plants having damp foliage going into the night. Always keep trees in optimal health by practicing to avoid stress which increases disease susceptibility. to If the problem persists, the fungicide Chlorothalonil offers a chemical control option and should be applied in early spring to protect the new growth. Several applications are needed. Colorado Blue Spruce naturally grows at higher elevations and is not native to our Illinois region, which puts it at a disadvantage and makes it more susceptible to pest and disease damage. It is a good practice to select native plants that are adapted to local environmental conditions.

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