Spruce: Oil discoloration of foliage

categories: Conifers Ornamentals Spruce Spruce Diseases

revision date: 2023-02-07 12:00

Spruce tree with bright green needles.
Discoloration on older foliage from oil application
Photo by: R. Maleike


Oil discoloration of spruce foliage is suspected when trees which normally have blue-green needles instead have bright green needles. Use of spray oils (to control insects, for instance) can permanently remove the waxy coating which gives the tree its blue color, allowing the underlying green of the needles to show through. The distribution of the discolored needles on the tree may be spotty. There is no harm to the tree; however, some aesthetic value may be lost. Growth occurring after the oil application will be blue.

Management Options

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

Do not use spray oils or other oil-based products on or upwind of blue-needle spruces.

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

  • None recommended