The lower branches of my Norway spruce look like they are dying.

There are fuzzy white puffs on the outer needles. Is there anything I can do?


Answer

You may have spruce bud scale affecting your tree (or a similar soft scale insect). Spruce bud scale (Physokermes piceae) are small and primarily attack Norway spruce in the Northeastern US and other US states. Their size and color make them look like buds and easy to overlook. They are round and reddish-brown in color, often clustered in-groups of 3 to 8 at the base of new shoots. Lower branches are more often attacked than higher branches and can die back entirely if numbers are large or the tree is under other stress.
 
The insects overwinter under needles and move out onto branches in spring. It is when they begin to produce honeydew that supports foamy, white or sooty black looking mold that they are most likely to be noticed. An article on soft scale from Michigan State University  has a photo of the appearance of these scale insects that you can use to examine your tree.
 
There are management options that include careful removal of affected branches, use of beneficial insects (low effectiveness in an outdoor setting), horticultural oils and chemical products. The crawler phase of the insect occurs just once a year in late summer/ early spring. This is the time that the scale insects are most vulnerable and treatment is likely to be most effective.
 
You should have a certified arborist examine the tree to determine the extent of the problem and describe the options that are likely to be effective. Trees under stress frequently have more than one factor impacting their health and the tree may need additional support to allow it to fight its battles vigorously - like soil improvement and water during dry periods.
 
If the damage to the tree is spread randomly throughout the tree and the white substance is resinous, and closer to the trunk or along dying branches, that is more likely to be Cytospora canker caused by the fungus Leucostoma kunzei. Cytospora canker is less common in Norway spruces but a significant problem for Colorado blue spruce that has been stressed by environmental conditions.
 
Courtesy of NYBG Plant Information Service
  • Last Updated May 17, 2024
  • Views 26
  • Answered By Leslie Coleman

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