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Juniper Scale

| By | Pests

Juniper Scale (Carulaspis juniperi)

GDD Window (base 50): 22-148 (dormant), 707-1260 (crawlers)

Overview:​​​

  • Female covers are circular and white (1/16” in diameter) ​
  • Male covers are elongated and white, but smaller in size ​
  • Yellowish cast skins are attached to the surface of the waxy covering of both sexes ​
  • Adult females overwinter on the foliage =(dormant oil sprays?) ​
  • One generation per year  ​
  • Scales usually build up on the south side of shrubs, or the sides against buildings  ​
  • Crawlers start hatching by mid-June and can continue into July​
  • No symptoms with light infestations​
  • Heavy infestations can lead to yellowed foliage and needle drop​
  • Unabated populations lead to dieback and unsightly plants
  • Host plants: Conifers (Juniper, false-cypress, Leyland cypress, arborvitae)​

Management:

Cultural Practices:
  • Natural predators:  brown lacewings, green lacewings, lady beetles, &  Parasitoid wasps ​
  • Prevent dusty conditions​
  • Reduce plant stress​
  • Dispose of heavily infested plants 
Materials:
  • Contact insecticides:​
    • Carbamates [1A]: carbaryl​
    • Pyrethroids [3A]: –thrins​
    • Organophosphates [1B]: acephate (translaminar), malathion​
  • Considerations:​
    • Will harm non-target species​
    • Timing is essential in controlling armored scales (target crawler stage before waxy covering forms)​
  • Systemic insecticides:​
    • Neonicotinoids [4A]: dinotefuran, acetamiprid, thiamethoxam​
    • Tetronic acids [23}: spirotetramat 
Biorationals:
  • Insecticidal soaps and Horticultural oils​
    • Neem oil​
  • Insect growth regulators:​
    • Pyriproxyfen [7A]​
    • Buprofezin [16]
Foliage of a false-cypress branch heavily infested with Juniper Scales. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)
Test for scale viability with a sharp pin to determine if body fluids emerge. If no fluids are present, then only the cover remains or the scale body is desiccated & dead.(Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)
The waxy cover is not attached to the actual armored scale insect & can be removed. Unlike the leathery exoskeleton of soft scales that cannot be removed. (Photo Credit: Steven K. Rettke, rutgers Coop. Ext.)
Disclaimer – Materials do not cover all possible control scenarios and are intended for licensed professionals. Tradenames do not imply endorsement and are used as examples. You must strictly follow the label for each compound prior to use. Rutgers is not responsible form is used materials or damages thereof. The label is the law. Labels will provide detailed information on use and restrictions. Additionally, application intervals, compatibility, surfactant use, PHI, PPE, important and other key information is described in detail. Always discuss treatments with your local agents. Note: Neonicotinoids can only be legally applied in commercial agriculture settings by licensed applicators. Guidelines and recommendations made in this presentation are specific to the state of New Jersey.