What is it?
The pine needle scale is a native microscopic insect, it overwinters as an egg under a hard, waxy, white scale. Although it is called pine needle scale, it attacks spruce as well.
Symptoms
- A group of white, waxy, oval scales (3mm long) appear on needles.
- Severe infestation will cause foliage to turn yellow.
- Over 20 scales per spruce needle and over 50 per pine needle is considered as severe.
Damages
- The insects extract sap from needles and cause needles turn yellow and drop prematurely.
- Trees will reduce vigor and annual growth after repeated infestation.
- Severe infestation can seriously deform or kill low vigor trees.
What to do?
- Keep your trees healthy is the first defense to any pests and diseases.
- Introduce natural enemies such as lady bugs and parasitoid wasps can significantly control population.
- Apply horticultural oils in early spring before the egg is protected by the white shell, oil can suffocate the immature scales.
- Insecticides can be highly effective on severe infestation with right timing and adequate amount, but it will also kill beneficial insects and might be toxic to human.
- If the insect population is low, prune out infested branches can be helpful. Otherwise, removal should be considered to protect the remaining healthy plants.
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