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Lots of people love the look of a blue spruce. The magnificent color of the silver-blue-green needles truly makes this evergreen an American favorite.

The biggest problem we often get asked about is needle cast. This disease is most common in trees growing outside of their native range, like our lovely blue spruce, which is native to Colorado.

Also known as rhizosphaera, needle cast, infects new growth during the growing season. However, you may not notice your tree has it until late winter or early spring. Needles will look yellow or get odd colored spots. If you look at some of the infected needles that fall you’ll see black fungal. The disease typically starts at the bottom of the tree infecting the lower inner needles first.  Click here to see if you’re tree is in jeopardy  

So what can you do to protect your blue spruce? The key is catching the needle cast early and treating right away, says friend of the show, Arborist Max Bigelow. 

“You have to catch it early.  I have had good results using chlorothalonil (Daconil.) Start treatments when new growths comes out and add another treatment in August which seems to help also.” 

Needle cast is hard to get rid of, but if do as Max suggested, there is hope! Be sure to keep special attention to your tree, especially this time of year. Even if you don’t see any issues, spraying a fungicide right now, like Daconil, could save your tree in the long run.

For more Home and Garden tips check out the highlights from our last show!


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