What is it?
Spruce spider mites are microscopic in dark green to dark brown color. They begin feeding around mid-May, continuing their activity throughout the entire growing period. They mainly attack conifer such as pine and spruce, by sucking out the sap from the needle. They can generate multiple generations annually, leading to reduce tree vigor and eventually death.
Symptoms
- A silken, fine webbing on twigs.
- Yellow and brown needles, premature needle drop and branch death with heavy infestation.
- Shake a branch over white paper. You should see tiny, dark mites are quickly moving. Pressing the paper in half, mites are likely present if red smears appear.
Damages
- The tree will be covered in a dusty substance, affecting its appearance.
- By sucking out the sap while feeding, infested needles will gradually turn yellow and drop.
- The damage initiates internally and subsequently progresses outwards and upwards.
- Heavy infestations can kill branches or even the whole tree.
What to do?
- Keep your tree hydrated and moist can help prevent infestation.
- Introduce natural enemies such as lady bugs and parasitic wasps.
- Washing your tree with strong water pressure can help wash off the mites.
- Prune your conifer trees and remove dead branches can help improve airflow and allow sunlight to get in.
- High pressure of insecticides can be used by a certified pesticide applicator.
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