Browning spruce trees (loss of needles)

Browning spruce trees  (loss of needles)

Our arborists have noticed many spruce trees showing signs of disease this spring.  If you are noticing your spruce tree(s) starting to look a bit ragged, with thinning branches and loss of needles, there is a good chance that a fungus is to blame.  The first noticeable sign of problems usually is the loss of the innermost needles on the lower branches.  As it spreads, the branch will become only green on the outermost area, and eventually the entire branch will die.  If left unchecked, the disease continues to march up higher on the canopy.

The most likely culprit is Rhizasphaeara needle cast disease.  The tree most susceptible to the disease is Colorado blue spruce. This spruce species is a commonly planted tree within landscape settings.  These trees are prized for their lush growth and bluish tinted needles, though some verities have a more conventional green color to them.  Other evergreen trees such as Austrian pine, Douglas fir, and white pine can also be affected by the disease, though it is much less common to see.

Where does Rhizasphaeara needlecast disease come from?

The fungus produces spores that can be blown thru the wind, or splashed by rain water to healthy branches or trees.  Cool, moist weather promotes the spread of the disease.  Overcrowded spruce plantings or mature trees provide the perfect environment for the fungus to grow and multiply.   These areas tend to have more shade and do not dry as quickly.  The fungus can be spread quite easily from branch to branch or tree to tree.

How do I save a tree with Rhizasphaera needlecast?

Pruning and fungicide applications are the answer.  Provide more air flow and spacing between trees and branches so that they dry out faster after rains, and make it harder for the fungal spores to advance.

Hoppe Tree Service can also inspect your trees and develop a program that will consist of a series of fungicide sprays to the foliage to protect new growth from the disease.  Applications are timed roughly three to four weeks apart thru the growing season.  We also can provide pruning and removal services.

Our arborists are well versed in identification of this disease and it is important to catch the problem early before it is too late to recover.

August Hoppe

Certified Arborist WI-0477A

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