Brown needles and webbing in small clumps that can be easily pulled apart are symptoms of the spruce needleminer. This tiny caterpillar feeds inside the needles, moving from needle to needle and leaving the small exit holes at the base of each needle. The detached needles accumulate in webbing made by the caterpillars. Damage is typically more unsightly than fatal. Control suggestions are to prune off and destroy infested stems if practical. Some resources suggest "washing" the needle debris from small trees with a forceful stream of water from the garden hose. Contact insecticides should be applied when the caterpillars are active, which is early spring (till mid-May according to some resources). Most ornamental insecticides labeled for spruce trees should be effective.
Damage from spruce needleminer
Damage from spruce needleminer
Holes at base of needles from spruce needleminer
Adult spruce needleminer moths
Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Horticulture and Home Pest News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on May 20, 2009. The information contained within may not be the most current and accurate depending on when it is accessed.