Skip to main content

Calico Scale

| By | Pests

Calico Scale (Eulecanium cerasorum)

GDD Window (base 50): 750-1200 (all eggs hatched by 1500 GDD)

Overview:​​​

  • Rounded, dome-shaped insects with a mottled brown and white pattern, up to ¼” in diameter​
  • Crawlers emerge from mid-June into August​
  • Crawlers are white and turn yellow, settling along leaf veins​
  • Overwinter on bark as 2nd instar nymphs & become adults in spring​
  • Causes honeydew and sooty mold, branch dieback and reduced vigor in heavily infested plants​
  • Feeding in the summer usually does not cause severe symptoms​
  • Can cause leaf yellowing, stunting, and premature shedding ​
  • Host plants:  many hosts (Deciduous)​
    • Shade trees (elm, zelkova, sweetgum, maple, honey locust)​
    • Flowering trees (dogwood, star magnolia, cherry, crabapple)​
    • Woody plants (firethorn, wisteria)

Management:

Cultural Practices:
  • Natural predators: lady beetles, parasitic wasps​
  • Monitor populations and remove scales manually​
  • Reduce plant stress​
  • Prune heavily infested branches​
Materials:
  • Contact insecticides:​
    • Pyrethroids [3]: –thrins​
    • Carbamates [1A]: carbaryl​
  • Systemic insecticides:​
    • Neonicotinoids [4A]: imidacloprid, dinotefuran​
    • Organophosphates [1B]: acephate ​
  • Considerations:​
    • Will harm non-target species​
    • Target sprays during crawler stage​
Biorationals:
  • Horticultural oils​
  • Insecticidal soap​
  • Neonic: acetamiprid​
  • Buprofezin (IGR)​
  • Pyriproxyfen (IGR)​

Resources:

Some Key Soft Scale Pests in the Landscape – PPA

Landscape Pest Notes for Late June 2023 – PPA

Mature Calico scale females feeding on branch stems are plumped-up & preparing to lay eggs. The black-white “calico” coloration is most prominent during this stage. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)
Thousands of calico scale eggs will hatch & emerge as crawlers from under dead female body. After hatching, crawlers will migrate to leaves & feed along leaf veins. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)
Larger, dark colored 2nd instar soft scale nymphs migrated from leaves to overwinter on branches & stems. They are highly vulnerable to predators during this stage. (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.