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Spruce Spider mite

One of the most common spider mites occurring in nursery production is the spruce spider mite (SSM), Oligonychus ununguis. It is the predominant spider mite affecting conifers in the Pacific northwest and elsewhere.

The following links have useful images and information about spruce spider mite.

Spruce spider mite: Pennsylvania Department of Agriculture. Entomology Circular No. 190. One of the most informative websites available on spruce spider mite.

Spruce spider mite: Pennsylvania Department of Agriculture. Again, the PDA has another useful website, this one with images. Entomology Circular No. 62.

Spruce Spider Mite Fact Sheet. Penn State Woody Ornamental Integrated Pest Management

Spruce spider mite. University of Minnesota.
Good images and useful information.

Spruce spider mite fact sheet. PNW Insect Management Handbook (online). Good information for Pacific Northwest SSM populations.

The following pesticides are listed in the PNW Insect Mangement Handbook for management of SSM.

1. abamectin

2. bifenazate—Good coverage is especially important with bifenazate (Floramite).

3. dicofol—Mites have developed resistance to dicofol in some areas.

4. etoxazole

5. fenbutatin oxide

6. fenpropathrin

7. fenpyroximate

8. hexythiazox

9. horticultural oil—Most effective against the egg stage of the mite life cycle.

10. insecticidal soap

11. propargite

12. pyridaben

13. spiromesifen

In all cases, follow the instructions on the pesticide label. The PNW Insect Management Handbook has no legal status, whereas the pesticide label is a legal document. Read the product label before making any pesticide applications.



Spruce spider mite damage to field grown arbovitae. Note browning of growth on the plant in the middle compared to nearby none-infested plants.
ssm damage in field-grown arbovitae
Photo: Rosetta
Closeup of spruce spider mite damage on arbovitae
Closeup of ssm damage on arbovitae
Photo: Rosetta
Spruce spider mite nymph
spruce spider mite larva
Photo: Kirin Elliott
Spruce spider mite nymphs
spruce spider mite larvae
Photo: Kirin Elliott
Spruce spider mite damage on scales
spruce spider mite damage
Photo: Kirin Elliott
Website editor:
Robin Rosetta
Page last modified 4/27/09

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