Spruce Needle Drop

Scientific Name: Setomelanomma holmii

Spruce Needle Drop (SNEED) is a branch disease of Colorado, Black Hills, and Norway Spruce that is only a problem on stressed trees. The pathogen was first described in France and in the past 10 years has been found on urban trees throughout the Midwestern United States. The disease is not found on or in the needles, but instead is found on the woody tissues at the base of the needles. It is not a problem on healthy trees in good growing environments. It will result in needle drop and branch death on trees that are unhealthy or are under a stress such as drought, root constriction, or are planted in poor soils.

Attacks: Colorado spruce, Black Hills (white) spruce, Norway spruce

What you will see:

• Apparently healthy trees with individual branches turning red.
• Older (2 and 3 year old) needles on the same branch turning red to brown and dropping
• No evidence of disease on the needles
  • clean stomata
• Black bumps on the branch tissue where the needles attach to the twig

Life cycle:

• Unknown
  • Trees either suppress infection until stressed
    or;
  • Become infected from over-wintering spores

Management of Spruce Needle Drop

Cultural practices:

• Prune out infected tissue
• Remove fallen needles
• Increase tree health
  • Remove girdling or constricting roots
  • Treat roots with prescription organic matter
  • Use soaker hoses during drought

Chemical Treatments:

• Treat branches with fungicide to prevent infection
  • Results unpredictable
  • Must be done in combination with cultural practices

An integrated approach

When caring for urban trees it is important to make a complete evaluation of all environmental conditions to accurately diagnose all stress factors and prescribe care based on specific circumstances. This prescriptive care will help a tree meet its full potential.

Awards & Affiliations

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