Answer: When needles turn a rusty color it usually indicates a drought condition and deeper watering can help you avoid this problem. If the rusty color is actually a coating on the leaves, it indicates a fungal disease. You'll need a microscopic examination of the affected foliage in order to confirm the diagnosis so you might want to collect a branch tip and take it to your local cooperative extension office for diagnosis. Helpful folks there can help determine the best course of action for your spruces. Contact Michigan Cooperative Extension, 775 Ball Ave, Grand Rapids, MI 49503-1307 phone (616) 336-3265? for the nearest office. Good luck with your trees.
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